(touch_file): Use message instead of printf.

[make.git] / main.c

/* Argument parsing and main program of GNU Make.
Copyright (C) 1988, 89, 90, 91, 94, 1995 Free Software Foundation, Inc.
This file is part of GNU Make.

GNU Make is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Make is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Make; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "make.h"
#include "commands.h"
#include "dep.h"
#include "file.h"
#include "variable.h"
#include "job.h"
#include "getopt.h"
#include <assert.h>


extern void print_variable_data_base ();
extern void print_dir_data_base ();
extern void print_rule_data_base ();
extern void print_file_data_base ();
extern void print_vpath_data_base ();

#ifndef HAVE_UNISTD_H
extern int chdir ();
#endif
#ifndef STDC_HEADERS
#ifndef sun                     /* Sun has an incorrect decl in a header.  */
extern void exit ();
#endif
extern double atof ();
#endif
extern char *mktemp ();

static void log_working_directory ();
static void print_data_base (), print_version ();
static void decode_switches (), decode_env_switches ();
static void define_makeflags ();
static char *quote_as_word ();
\f
/* The structure that describes an accepted command switch.  */

struct command_switch
  {
    char c;                     /* The switch character.  */

    enum                        /* Type of the value.  */
      {
        flag,                   /* Turn int flag on.  */
        flag_off,               /* Turn int flag off.  */
        string,                 /* One string per switch.  */
        positive_int,           /* A positive integer.  */
        floating,               /* A floating-point number (double).  */
        ignore                  /* Ignored.  */
      } type;

    char *value_ptr;    /* Pointer to the value-holding variable.  */

    unsigned int env:1;         /* Can come from MAKEFLAGS.  */
    unsigned int toenv:1;       /* Should be put in MAKEFLAGS.  */
    unsigned int no_makefile:1; /* Don't propagate when remaking makefiles.  */

    char *noarg_value;  /* Pointer to value used if no argument is given.  */
    char *default_value;/* Pointer to default value.  */

    char *long_name;            /* Long option name.  */
    char *argdesc;              /* Descriptive word for argument.  */
    char *description;          /* Description for usage message.  */
  };


/* The structure used to hold the list of strings given
   in command switches of a type that takes string arguments.  */

struct stringlist
  {
    char **list;        /* Nil-terminated list of strings.  */
    unsigned int idx;   /* Index into above.  */
    unsigned int max;   /* Number of pointers allocated.  */
  };


/* The recognized command switches.  */

/* Nonzero means do not print commands to be executed (-s).  */

int silent_flag;

/* Nonzero means just touch the files
   that would appear to need remaking (-t)  */

int touch_flag;

/* Nonzero means just print what commands would need to be executed,
   don't actually execute them (-n).  */

int just_print_flag;

/* Print debugging trace info (-d).  */

int debug_flag = 0;

/* Environment variables override makefile definitions.  */

int env_overrides = 0;

/* Nonzero means ignore status codes returned by commands
   executed to remake files.  Just treat them all as successful (-i).  */

int ignore_errors_flag = 0;

/* Nonzero means don't remake anything, just print the data base
   that results from reading the makefile (-p).  */

int print_data_base_flag = 0;

/* Nonzero means don't remake anything; just return a nonzero status
   if the specified targets are not up to date (-q).  */

int question_flag = 0;

/* Nonzero means do not use any of the builtin rules (-r).  */

int no_builtin_rules_flag = 0;

/* Nonzero means keep going even if remaking some file fails (-k).  */

int keep_going_flag;
int default_keep_going_flag = 0;

/* Nonzero means print directory before starting and when done (-w).  */

int print_directory_flag = 0;

/* Nonzero means ignore print_directory_flag and never print the directory.
   This is necessary because print_directory_flag is set implicitly.  */

int inhibit_print_directory_flag = 0;

/* Nonzero means print version information.  */

int print_version_flag = 0;

/* List of makefiles given with -f switches.  */

static struct stringlist *makefiles = 0;


/* Number of job slots (commands that can be run at once).  */

unsigned int job_slots = 1;
unsigned int default_job_slots = 1;

/* Value of job_slots that means no limit.  */

static unsigned int inf_jobs = 0;

/* Maximum load average at which multiple jobs will be run.
   Negative values mean unlimited, while zero means limit to
   zero load (which could be useful to start infinite jobs remotely
   but one at a time locally).  */

double max_load_average = -1.0;
double default_load_average = -1.0;

/* List of directories given with -C switches.  */

static struct stringlist *directories = 0;

/* List of include directories given with -I switches.  */

static struct stringlist *include_directories = 0;

/* List of files given with -o switches.  */

static struct stringlist *old_files = 0;

/* List of files given with -W switches.  */

static struct stringlist *new_files = 0;

/* If nonzero, we should just print usage and exit.  */

static int print_usage_flag = 0;

/* If nonzero, we should print a warning message
   for each reference to an undefined variable.  */

int warn_undefined_variables_flag;
\f
/* The table of command switches.  */

static const struct command_switch switches[] =
  {
    { 'b', ignore, 0, 0, 0, 0, 0, 0,
        0, 0,
        "Ignored for compatibility" },
    { 'C', string, (char *) &directories, 0, 0, 0, 0, 0,
        "directory", "DIRECTORY",
        "Change to DIRECTORY before doing anything" },
    { 'd', flag, (char *) &debug_flag, 1, 1, 0, 0, 0,
        "debug", 0,
        "Print lots of debugging information" },
    { 'e', flag, (char *) &env_overrides, 1, 1, 0, 0, 0,
        "environment-overrides", 0,
        "Environment variables override makefiles" },
    { 'f', string, (char *) &makefiles, 0, 0, 0, 0, 0,
        "file", "FILE",
        "Read FILE as a makefile" },
    { 'h', flag, (char *) &print_usage_flag, 0, 0, 0, 0, 0,
        "help", 0,
        "Print this message and exit" },
    { 'i', flag, (char *) &ignore_errors_flag, 1, 1, 0, 0, 0,
        "ignore-errors", 0,
        "Ignore errors from commands" },
    { 'I', string, (char *) &include_directories, 1, 1, 0, 0, 0,
        "include-dir", "DIRECTORY",
        "Search DIRECTORY for included makefiles" },
    { 'j', positive_int, (char *) &job_slots, 1, 1, 0,
        (char *) &inf_jobs, (char *) &default_job_slots,
        "jobs", "N",
        "Allow N jobs at once; infinite jobs with no arg" },
    { 'k', flag, (char *) &keep_going_flag, 1, 1, 0,
        0, (char *) &default_keep_going_flag,
        "keep-going", 0,
        "Keep going when some targets can't be made" },
    { 'l', floating, (char *) &max_load_average, 1, 1, 0,
        (char *) &default_load_average, (char *) &default_load_average,
        "load-average", "N",
        "Don't start multiple jobs unless load is below N" },
    { 'm', ignore, 0, 0, 0, 0, 0, 0,
        0, 0,
        "-b" },
    { 'n', flag, (char *) &just_print_flag, 1, 1, 1, 0, 0,
        "just-print", 0,
        "Don't actually run any commands; just print them" },
    { 'o', string, (char *) &old_files, 0, 0, 0, 0, 0,
        "old-file", "FILE",
        "Consider FILE to be very old and don't remake it" },
    { 'p', flag, (char *) &print_data_base_flag, 1, 1, 0, 0, 0,
        "print-data-base", 0,
        "Print make's internal database" },
    { 'q', flag, (char *) &question_flag, 1, 1, 1, 0, 0,
        "question", 0,
        "Run no commands; exit status says if up to date" },
    { 'r', flag, (char *) &no_builtin_rules_flag, 1, 1, 0, 0, 0,
        "no-builtin-rules", 0,
        "Disable the built-in implicit rules" },
    { 's', flag, (char *) &silent_flag, 1, 1, 0, 0, 0,
        "silent", 0,
        "Don't echo commands" },
    { 'S', flag_off, (char *) &keep_going_flag, 1, 1, 0,
        0, (char *) &default_keep_going_flag,
        "no-keep-going", 0,
        "Turns off -k" },
    { 't', flag, (char *) &touch_flag, 1, 1, 1, 0, 0,
        "touch", 0,
        "Touch targets instead of remaking them" },
    { 'v', flag, (char *) &print_version_flag, 1, 1, 0, 0, 0,
        "version", 0,
        "Print the version number of make and exit" },
    { 'w', flag, (char *) &print_directory_flag, 1, 1, 0, 0, 0,
        "print-directory", 0,
        "Print the current directory" },
    { 2, flag, (char *) &inhibit_print_directory_flag, 1, 1, 0, 0, 0,
        "no-print-directory", 0,
        "Turn off -w, even if it was turned on implicitly" },
    { 'W', string, (char *) &new_files, 0, 0, 0, 0, 0,
        "what-if", "FILE",
        "Consider FILE to be infinitely new" },
    { 3, flag, (char *) &warn_undefined_variables_flag, 1, 1, 0, 0, 0,
        "warn-undefined-variables", 0,
        "Warn when an undefined variable is referenced" },
    { '\0', }
  };

/* Secondary long names for options.  */

static struct option long_option_aliases[] =
  {
    { "quiet",          no_argument,            0, 's' },
    { "stop",           no_argument,            0, 'S' },
    { "new-file",       required_argument,      0, 'W' },
    { "assume-new",     required_argument,      0, 'W' },
    { "assume-old",     required_argument,      0, 'o' },
    { "max-load",       optional_argument,      0, 'l' },
    { "dry-run",        no_argument,            0, 'n' },
    { "recon",          no_argument,            0, 'n' },
    { "makefile",       required_argument,      0, 'f' },
  };

/* The usage message prints the descriptions of options starting in
   this column.  Make sure it leaves enough room for the longest
   description to fit in less than 80 characters.  */

#define DESCRIPTION_COLUMN      30

/* List of goal targets.  */

static struct dep *goals, *lastgoal;

/* List of variables which were defined on the command line
   (or, equivalently, in MAKEFLAGS).  */

struct command_variable
  {
    struct command_variable *next;
    struct variable *variable;
  };
static struct command_variable *command_variables;
\f
/* The name we were invoked with.  */

char *program;

/* Our current directory before processing any -C options.  */

char *directory_before_chdir;

/* Our current directory after processing all -C options.  */

char *starting_directory;

/* Value of the MAKELEVEL variable at startup (or 0).  */

unsigned int makelevel;

/* First file defined in the makefile whose name does not
   start with `.'.  This is the default to remake if the
   command line does not specify.  */

struct file *default_goal_file;

/* Pointer to structure for the file .DEFAULT
   whose commands are used for any file that has none of its own.
   This is zero if the makefiles do not define .DEFAULT.  */

struct file *default_file;

/* Nonzero if we have seen the magic `.POSIX' target.
   This turns on pedantic compliance with POSIX.2.  */

int posix_pedantic;
\f
/* Mask of signals that are being caught with fatal_error_signal.  */

#ifdef  POSIX
sigset_t fatal_signal_set;
#else
#ifdef  HAVE_SIGSETMASK
int fatal_signal_mask;
#endif
#endif

static struct file *
enter_command_line_file (name)
     char *name;
{
  if (name[0] == '\0')
    fatal ("empty string invalid as file name");

  if (name[0] == '~')
    {
      char *expanded = tilde_expand (name);
      if (expanded != 0)
        name = expanded;        /* Memory leak; I don't care.  */
    }

  /* This is also done in parse_file_seq, so this is redundant
     for names read from makefiles.  It is here for names passed
     on the command line.  */
  while (name[0] == '.' && name[1] == '/' && name[2] != '\0')
    {
      name += 2;
      while (*name == '/')
        /* Skip following slashes: ".//foo" is "foo", not "/foo".  */
        ++name;
    }
  
  if (*name == '\0')
    {
      /* It was all slashes!  Move back to the dot and truncate
         it after the first slash, so it becomes just "./".  */
      do
        --name;
      while (name[0] != '.');
      name[2] = '\0';
    }

  return enter_file (savestring (name, strlen (name)));
}

/* Toggle -d on receipt of SIGUSR1.  */

static RETSIGTYPE
debug_signal_handler (sig)
     int sig;
{
  debug_flag = ! debug_flag;
}

int
main (argc, argv, envp)
     int argc;
     char **argv;
     char **envp;
{
  extern void init_dir ();
  extern RETSIGTYPE fatal_error_signal (), child_handler ();
  register struct file *f;
  register unsigned int i;
  char **p;
  struct dep *read_makefiles;
  PATH_VAR (current_directory);

  default_goal_file = 0;
  reading_filename = 0;
  reading_lineno_ptr = 0;
  
#if !defined (HAVE_STRSIGNAL) && !defined (HAVE_SYS_SIGLIST)
  signame_init ();
#endif

#ifdef  POSIX
  sigemptyset (&fatal_signal_set);
#define ADD_SIG(sig)    sigaddset (&fatal_signal_set, sig)
#else
#ifdef  HAVE_SIGSETMASK
  fatal_signal_mask = 0;
#define ADD_SIG(sig)    fatal_signal_mask |= sigmask (sig)
#else
#define ADD_SIG(sig)
#endif
#endif

#define FATAL_SIG(sig)                                                        \
  if (signal ((sig), fatal_error_signal) == SIG_IGN)                          \
    (void) signal ((sig), SIG_IGN);                                           \
  else                                                                        \
    ADD_SIG (sig);

  FATAL_SIG (SIGHUP);
  FATAL_SIG (SIGQUIT);
  FATAL_SIG (SIGINT);
  FATAL_SIG (SIGTERM);

#ifdef  SIGDANGER
  FATAL_SIG (SIGDANGER);
#endif
#ifdef SIGXCPU
  FATAL_SIG (SIGXCPU);
#endif
#ifdef SIGXFSZ
  FATAL_SIG (SIGXFSZ);
#endif

#undef  FATAL_SIG

  /* Make sure stdout is line-buffered.  */

#ifdef  HAVE_SETLINEBUF
  setlinebuf (stdout);
#else
#ifndef SETVBUF_REVERSED
  setvbuf (stdout, (char *) 0, _IOLBF, BUFSIZ);
#else   /* setvbuf not reversed.  */
  /* Some buggy systems lose if we pass 0 instead of allocating ourselves.  */
  setvbuf (stdout, _IOLBF, xmalloc (BUFSIZ), BUFSIZ);
#endif  /* setvbuf reversed.  */
#endif  /* setlinebuf missing.  */

  /* Initialize the directory hashing code.  */
  init_dir ();

  /* Figure out where this program lives.  */

  if (argv[0] == 0)
    argv[0] = "";
  if (argv[0][0] == '\0')
    program = "make";
  else 
    {
      program = rindex (argv[0], '/');
#ifdef __MSDOS__
      if (program == 0)
        program = rindex (argv[0], '\\');
      if (program == 0)
        program = rindex (argv[0], ':');
#endif
      if (program == 0)
        program = argv[0];
      else
        ++program;
    }

  /* Set up to access user data (files).  */
  user_access ();

  /* Figure out where we are.  */

  if (getcwd (current_directory, GET_PATH_MAX) == 0)
    {
#ifdef  HAVE_GETCWD
      perror_with_name ("getcwd: ", "");
#else
      error ("getwd: %s", current_directory);
#endif
      current_directory[0] = '\0';
      directory_before_chdir = 0;
    }
  else
    directory_before_chdir = savestring (current_directory,
                                         strlen (current_directory));

  /* Read in variables from the environment.  It is important that this be
     done before $(MAKE) is are figured out so its definitions will not be
     one from the environment.  */

  for (i = 0; envp[i] != 0; ++i)
    {
      register char *ep = envp[i];
      while (*ep != '=')
        ++ep;
      /* The result of pointer arithmetic is cast to unsigned int for
         machines where ptrdiff_t is a different size that doesn't widen
         the same.  */
      define_variable (envp[i], (unsigned int) (ep - envp[i]),
                       ep + 1, o_env, 1)
        /* Force exportation of every variable culled from the environment.
           We used to rely on target_environment's v_default code to do this.
           But that does not work for the case where an environment variable
           is redefined in a makefile with `override'; it should then still
           be exported, because it was originally in the environment.  */
        ->export = v_export;
    }

  /* Decode the switches.  */

  decode_env_switches ("MAKEFLAGS", 9);
#if 0
  /* People write things like:
        MFLAGS="CC=gcc -pipe" "CFLAGS=-g"
     and we set the -p, -i and -e switches.  Doesn't seem quite right.  */
  decode_env_switches ("MFLAGS", 6);
#endif
  decode_switches (argc, argv, 0);

  /* Print version information.  */

  if (print_version_flag || print_data_base_flag || debug_flag)
    print_version ();

  /* `make --version' is supposed to just print the version and exit.  */
  if (print_version_flag)
    die (0);

#ifndef __MSDOS__
  /* Set the "MAKE_COMMAND" variable to the name we were invoked with.
     (If it is a relative pathname with a slash, prepend our directory name
     so the result will run the same program regardless of the current dir.
     If it is a name with no slash, we can only hope that PATH did not
     find it in the current directory.)  */

  if (current_directory[0] != '\0'
      && argv[0] != 0 && argv[0][0] != '/' && index (argv[0], '/') != 0)
    argv[0] = concat (current_directory, "/", argv[0]);
#endif

  /* The extra indirection through $(MAKE_COMMAND) is done
     for hysterical raisins.  */
  (void) define_variable ("MAKE_COMMAND", 12, argv[0], o_default, 0);
  (void) define_variable ("MAKE", 4, "$(MAKE_COMMAND)", o_default, 1);

  if (command_variables != 0)
    {
      struct command_variable *cv;
      struct variable *v;
      unsigned int len = 0;
      char *value, *p;

      /* Figure out how much space will be taken up by the command-line
         variable definitions.  */
      for (cv = command_variables; cv != 0; cv = cv->next)
        {
          v = cv->variable;
          len += 2 * strlen (v->name);
          if (! v->recursive)
            ++len;
          ++len;
          len += 2 * strlen (v->value);
        }

      /* Now allocate a buffer big enough and fill it.  */
      p = value = (char *) alloca (len);
      for (cv = command_variables; cv != 0; cv = cv->next)
        {
          v = cv->variable;
          p = quote_as_word (p, v->name, 0);
          if (! v->recursive)
            *p++ = ':';
          *p++ = '=';
          p = quote_as_word (p, v->value, 0);
          *p++ = ' ';
        }
      p[-1] = '\0';             /* Kill the final space and terminate.  */

      /* Define an unchangeable variable with a name that no POSIX.2
         makefile could validly use for its own variable.  */
      (void) define_variable ("-*-command-variables-*-", 23,
                              value, o_automatic, 0);

      /* Define the variable; this will not override any user definition.
         Normally a reference to this variable is written into the value of
         MAKEFLAGS, allowing the user to override this value to affect the
         exported value of MAKEFLAGS.  In POSIX-pedantic mode, we cannot
         allow the user's setting of MAKEOVERRIDES to affect MAKEFLAGS, so
         a reference to this hidden variable is written instead. */
      (void) define_variable ("MAKEOVERRIDES", 13,
                              "${-*-command-variables-*-}", o_env, 1);
    }

  /* If there were -C flags, move ourselves about.  */
  if (directories != 0)
    for (i = 0; directories->list[i] != 0; ++i)
      {
        char *dir = directories->list[i];
        if (dir[0] == '~')
          {
            char *expanded = tilde_expand (dir);
            if (expanded != 0)
              dir = expanded;
          }
        if (chdir (dir) < 0)
          pfatal_with_name (dir);
        if (dir != directories->list[i])
          free (dir);
      }

  /* Figure out the level of recursion.  */
  {
    struct variable *v = lookup_variable ("MAKELEVEL", 9);
    if (v != 0 && *v->value != '\0' && *v->value != '-')
      makelevel = (unsigned int) atoi (v->value);
    else
      makelevel = 0;
  }

  /* Except under -s, always do -w in sub-makes and under -C.  */
  if (!silent_flag && (directories != 0 || makelevel > 0))
    print_directory_flag = 1;

  /* Let the user disable that with --no-print-directory.  */
  if (inhibit_print_directory_flag)
    print_directory_flag = 0;

  /* Construct the list of include directories to search.  */

  construct_include_path (include_directories == 0 ? (char **) 0
                          : include_directories->list);

  /* Figure out where we are now, after chdir'ing.  */
  if (directories == 0)
    /* We didn't move, so we're still in the same place.  */
    starting_directory = current_directory;
  else
    {
      if (getcwd (current_directory, GET_PATH_MAX) == 0)
        {
#ifdef  HAVE_GETCWD
          perror_with_name ("getcwd: ", "");
#else
          error ("getwd: %s", current_directory);
#endif
          starting_directory = 0;
        }
      else
        starting_directory = current_directory;
    }

  /* Tell the user where he is.  */

  if (print_directory_flag)
    log_working_directory (1);

  /* Read any stdin makefiles into temporary files.  */

  if (makefiles != 0)
    {
      register unsigned int i;
      for (i = 0; i < makefiles->idx; ++i)
        if (makefiles->list[i][0] == '-' && makefiles->list[i][1] == '\0')
          {
            /* This makefile is standard input.  Since we may re-exec
               and thus re-read the makefiles, we read standard input
               into a temporary file and read from that.  */
            FILE *outfile;

            /* Make a unique filename.  */
#ifdef HAVE_MKTEMP
            static char name[] = "/tmp/GmXXXXXX";
            (void) mktemp (name);
#else
            static char name[L_tmpnam];
            (void) tmpnam (name);
#endif

            outfile = fopen (name, "w");
            if (outfile == 0)
              pfatal_with_name ("fopen (temporary file)");
            while (!feof (stdin))
              {
                char buf[2048];
                int n = fread (buf, 1, sizeof(buf), stdin);
                if (n > 0 && fwrite (buf, 1, n, outfile) != n)
                  pfatal_with_name ("fwrite (temporary file)");
              }
            /* Try to make sure we won't remake the temporary
               file when we are re-exec'd.  Kludge-o-matic!  */
            fprintf (outfile, "%s:;\n", name);
            (void) fclose (outfile);

            /* Replace the name that read_all_makefiles will
               see with the name of the temporary file.  */
            {
              char *temp;
              /* SGI compiler requires alloca's result be assigned simply.  */
              temp = (char *) alloca (sizeof (name));
              bcopy (name, temp, sizeof (name));
              makefiles->list[i] = temp;
            }

            /* Make sure the temporary file will not be remade.  */
            f = enter_file (savestring (name, sizeof name - 1));
            f->updated = 1;
            f->update_status = 0;
            f->command_state = cs_finished;
            /* Let it be removed when we're done.  */
            f->intermediate = 1;
            /* But don't mention it.  */
            f->dontcare = 1;
          }
    }

  /* Set up to handle children dying.  This must be done before
     reading in the makefiles so that `shell' function calls will work.  */

#ifdef SIGCHLD
  (void) signal (SIGCHLD, child_handler);
#endif
#ifdef SIGCLD
  (void) signal (SIGCLD, child_handler);
#endif

  /* Let the user send us SIGUSR1 to toggle the -d flag during the run.  */
#ifdef SIGUSR1
  (void) signal (SIGUSR1, debug_signal_handler);
#endif

  /* Define the initial list of suffixes for old-style rules.  */

  set_default_suffixes ();

  /* Define the file rules for the built-in suffix rules.  These will later
     be converted into pattern rules.  We used to do this in
     install_default_implicit_rules, but since that happens after reading
     makefiles, it results in the built-in pattern rules taking precedence
     over makefile-specified suffix rules, which is wrong.  */

  install_default_suffix_rules ();

  /* Define some internal and special variables.  */

  define_automatic_variables ();

  /* Set up the MAKEFLAGS and MFLAGS variables
     so makefiles can look at them.  */

  define_makeflags (0, 0);

  /* Define the default variables.  */
  define_default_variables ();

  /* Read all the makefiles.  */

  default_file = enter_file (".DEFAULT");

  read_makefiles
    = read_all_makefiles (makefiles == 0 ? (char **) 0 : makefiles->list);

  /* Decode switches again, in case the variables were set by the makefile.  */
  decode_env_switches ("MAKEFLAGS", 9);
#if 0
  decode_env_switches ("MFLAGS", 6);
#endif

  /* Set up MAKEFLAGS and MFLAGS again, so they will be right.  */

  define_makeflags (1, 0);

  /* Make each `struct dep' point at the `struct file' for the file
     depended on.  Also do magic for special targets.  */

  snap_deps ();

  /* Convert old-style suffix rules to pattern rules.  It is important to
     do this before installing the built-in pattern rules below, so that
     makefile-specified suffix rules take precedence over built-in pattern
     rules.  */

  convert_to_pattern ();

  /* Install the default implicit pattern rules.
     This used to be done before reading the makefiles.
     But in that case, built-in pattern rules were in the chain
     before user-defined ones, so they matched first.  */

  install_default_implicit_rules ();

  /* Compute implicit rule limits.  */

  count_implicit_rule_limits ();

  /* Construct the listings of directories in VPATH lists.  */

  build_vpath_lists ();

  /* Mark files given with -o flags as very old (00:00:01.00 Jan 1, 1970)
     and as having been updated already, and files given with -W flags as
     brand new (time-stamp as far as possible into the future).  */

  if (old_files != 0)
    for (p = old_files->list; *p != 0; ++p)
      {
        f = enter_command_line_file (*p);
        f->last_mtime = (time_t) 1;
        f->updated = 1;
        f->update_status = 0;
        f->command_state = cs_finished;
      }

  if (new_files != 0)
    {
      for (p = new_files->list; *p != 0; ++p)
        {
          f = enter_command_line_file (*p);
          f->last_mtime = NEW_MTIME;
        }
    }

  if (read_makefiles != 0)
    {
      /* Update any makefiles if necessary.  */

      time_t *makefile_mtimes = 0;
      unsigned int mm_idx = 0;

      if (debug_flag)
        puts ("Updating makefiles....");

      /* Remove any makefiles we don't want to try to update.
         Also record the current modtimes so we can compare them later.  */
      {
        register struct dep *d, *last;
        last = 0;
        d = read_makefiles;
        while (d != 0)
          {
            register struct file *f = d->file;
            if (f->double_colon)
              for (f = f->double_colon; f != NULL; f = f->prev)
                {
                  if (f->deps == 0 && f->cmds != 0)
                    {
                      /* This makefile is a :: target with commands, but
                         no dependencies.  So, it will always be remade.
                         This might well cause an infinite loop, so don't
                         try to remake it.  (This will only happen if
                         your makefiles are written exceptionally
                         stupidly; but if you work for Athena, that's how
                         you write your makefiles.)  */

                      if (debug_flag)
                        printf ("Makefile `%s' might loop; not remaking it.\n",
                                f->name);

                      if (last == 0)
                        read_makefiles = d->next;
                      else
                        last->next = d->next;

                      /* Free the storage.  */
                      free ((char *) d);

                      d = last == 0 ? 0 : last->next;

                      break;
                    }
                }
            if (f == NULL || !f->double_colon)
              {
                if (makefile_mtimes == 0)
                  makefile_mtimes = (time_t *) xmalloc (sizeof (time_t));
                else
                  makefile_mtimes = (time_t *)
                    xrealloc ((char *) makefile_mtimes,
                              (mm_idx + 1) * sizeof (time_t));
                makefile_mtimes[mm_idx++] = file_mtime_no_search (d->file);
                last = d;
                d = d->next;
              }
          }
      } 

      /* Set up `MAKEFLAGS' specially while remaking makefiles.  */
      define_makeflags (1, 1);

      switch (update_goal_chain (read_makefiles, 1))
        {
        case 1:
        default:
#define BOGUS_UPDATE_STATUS 0
          assert (BOGUS_UPDATE_STATUS);
          break;
          
        case -1:
          /* Did nothing.  */
          break;
          
        case 2:
          /* Failed to update.  Figure out if we care.  */
          {
            /* Nonzero if any makefile was successfully remade.  */
            int any_remade = 0;
            /* Nonzero if any makefile we care about failed
               in updating or could not be found at all.  */
            int any_failed = 0;
            register unsigned int i;

            for (i = 0; read_makefiles != 0; ++i)
              {
                struct dep *d = read_makefiles;
                read_makefiles = d->next;
                if (d->file->updated)
                  {
                    /* This makefile was updated.  */
                    if (d->file->update_status == 0)
                      {
                        /* It was successfully updated.  */
                        any_remade |= (file_mtime_no_search (d->file)
                                       != makefile_mtimes[i]);
                      }
                    else if (! (d->changed & RM_DONTCARE))
                      {
                        time_t mtime;
                        /* The update failed and this makefile was not
                           from the MAKEFILES variable, so we care.  */
                        error ("Failed to remake makefile `%s'.",
                               d->file->name);
                        mtime = file_mtime_no_search (d->file);
                        any_remade |= (mtime != (time_t) -1
                                       && mtime != makefile_mtimes[i]);
                      }
                  }
                else
                  /* This makefile was not found at all.  */
                  if (! (d->changed & RM_DONTCARE))
                    {
                      /* This is a makefile we care about.  See how much.  */
                      if (d->changed & RM_INCLUDED)
                        /* An included makefile.  We don't need
                           to die, but we do want to complain.  */
                        error ("Included makefile `%s' was not found.",
                               dep_name (d));
                      else
                        {
                          /* A normal makefile.  We must die later.  */
                          error ("Makefile `%s' was not found", dep_name (d));
                          any_failed = 1;
                        }
                    }

                free ((char *) d);
              }

            if (any_remade)
              goto re_exec;
            else if (any_failed)
              die (2);
            else
              break;
          }

        case 0:
        re_exec:
          /* Updated successfully.  Re-exec ourselves.  */

          remove_intermediates (0);

          if (print_data_base_flag)
            print_data_base ();

          if (print_directory_flag)
            log_working_directory (0);

          if (makefiles != 0)
            {
              /* These names might have changed.  */
              register unsigned int i, j = 0;
              for (i = 1; i < argc; ++i)
                if (!strcmp (argv[i], "-f")) /* XXX */
                  {
                    char *p = &argv[i][2];
                    if (*p == '\0')
                      argv[++i] = makefiles->list[j];
                    else
                      argv[i] = concat ("-f", makefiles->list[j], "");
                    ++j;
                  }
            }

          if (directories != 0 && directories->idx > 0)
            {
              char bad;
              if (directory_before_chdir != 0)
                {
                  if (chdir (directory_before_chdir) < 0)
                    {
                      perror_with_name ("chdir", "");
                      bad = 1;
                    }
                  else
                    bad = 0;
                }
              else
                bad = 1;
              if (bad)
                fatal ("Couldn't change back to original directory.");
            }

          for (p = environ; *p != 0; ++p)
            if (!strncmp (*p, "MAKELEVEL=", 10))
              {
                /* The SGI compiler apparently can't understand
                   the concept of storing the result of a function
                   in something other than a local variable.  */
                char *sgi_loses;
                sgi_loses = (char *) alloca (40);
                *p = sgi_loses;
                sprintf (*p, "MAKELEVEL=%u", makelevel);
                break;
              }

          if (debug_flag)
            {
              char **p;
              fputs ("Re-executing:", stdout);
              for (p = argv; *p != 0; ++p)
                printf (" %s", *p);
              puts ("");
            }

          fflush (stdout);
          fflush (stderr);

          exec_command (argv, environ);
          /* NOTREACHED */
        }
    }

  /* Set up `MAKEFLAGS' again for the normal targets.  */
  define_makeflags (1, 0);

  {
    int status;

    /* If there were no command-line goals, use the default.  */
    if (goals == 0)
      {
        if (default_goal_file != 0)
          {
            goals = (struct dep *) xmalloc (sizeof (struct dep));
            goals->next = 0;
            goals->name = 0;
            goals->file = default_goal_file;
          }
      }
    else
      lastgoal->next = 0;

    if (goals != 0)
      {
        /* Update the goals.  */

        if (debug_flag)
          puts ("Updating goal targets....");

        switch (update_goal_chain (goals, 0))
          {
          case -1:
            /* Nothing happened.  */
          case 0:
            /* Updated successfully.  */
            status = 0;
            break;
          case 2:
            /* Updating failed.  */
            status = 2;
            break;
          case 1:
            /* We are under -q and would run some commands.  */
            status = 1;
            break;
          default:
            abort ();
          }
      }
    else
      {
        if (read_makefiles == 0)
          fatal ("No targets specified and no makefile found");
        else
          fatal ("No targets");
      }

    /* Exit.  */
    die (status);
  }

  return 0;
}
\f
/* Parsing of arguments, decoding of switches.  */

static char options[1 + sizeof (switches) / sizeof (switches[0]) * 3];
static struct option long_options[(sizeof (switches) / sizeof (switches[0])) +
                                  (sizeof (long_option_aliases) /
                                   sizeof (long_option_aliases[0]))];

/* Fill in the string and vector for getopt.  */
static void
init_switches ()
{
  register char *p;
  register int c;
  register unsigned int i;

  if (options[0] != '\0')
    /* Already done.  */
    return;

  p = options;

  /* Return switch and non-switch args in order, regardless of
     POSIXLY_CORRECT.  Non-switch args are returned as option 1.  */
  *p++ = '-';

  for (i = 0; switches[i].c != '\0'; ++i)
    {
      long_options[i].name = (switches[i].long_name == 0 ? "" :
                              switches[i].long_name);
      long_options[i].flag = 0;
      long_options[i].val = switches[i].c;
      if (isalnum (switches[i].c))
        *p++ = switches[i].c;
      switch (switches[i].type)
        {
        case flag:
        case flag_off:
        case ignore:
          long_options[i].has_arg = no_argument;
          break;

        case string:
        case positive_int:
        case floating:
          if (isalnum (switches[i].c))
            *p++ = ':';
          if (switches[i].noarg_value != 0)
            {
              if (isalnum (switches[i].c))
                *p++ = ':';
              long_options[i].has_arg = optional_argument;
            }
          else
            long_options[i].has_arg = required_argument;
          break;
        }
    }
  *p = '\0';
  for (c = 0; c < (sizeof (long_option_aliases) /
                   sizeof (long_option_aliases[0]));
       ++c)
    long_options[i++] = long_option_aliases[c];
  long_options[i].name = 0;
}

static void
handle_non_switch_argument (arg, env)
     char *arg;
     int env;
{
  /* Non-option argument.  It might be a variable definition.  */
  struct variable *v;
  if (arg[0] == '-' && arg[1] == '\0')
    /* Ignore plain `-' for compatibility.  */
    return;
  v = try_variable_definition ((char *) 0, 0, arg, o_command);
  if (v != 0)
    {
      /* It is indeed a variable definition.  Record a pointer to
         the variable for later use in define_makeflags.  */
      struct command_variable *cv
        = (struct command_variable *) xmalloc (sizeof (*cv));
      cv->variable = v;
      cv->next = command_variables;
      command_variables = cv;
    }
  else if (! env)
    {
      /* Not an option or variable definition; it must be a goal
         target!  Enter it as a file and add it to the dep chain of
         goals.  */
      struct file *f = enter_command_line_file (arg);
      f->cmd_target = 1;
          
      if (goals == 0)
        {
          goals = (struct dep *) xmalloc (sizeof (struct dep));
          lastgoal = goals;
        }
      else
        {
          lastgoal->next
            = (struct dep *) xmalloc (sizeof (struct dep));
          lastgoal = lastgoal->next;
        }
      lastgoal->name = 0;
      lastgoal->file = f;
    }
}

/* Decode switches from ARGC and ARGV.
   They came from the environment if ENV is nonzero.  */

static void
decode_switches (argc, argv, env)
     int argc;
     char **argv;
     int env;
{
  int bad = 0;
  register const struct command_switch *cs;
  register struct stringlist *sl;
  register int c;

  /* getopt does most of the parsing for us.
     First, get its vectors set up.  */

  init_switches ();

  /* Let getopt produce error messages for the command line,
     but not for options from the environment.  */
  opterr = !env;
  /* Reset getopt's state.  */
  optind = 0;

  while (optind < argc)
    {
      /* Parse the next argument.  */
      c = getopt_long (argc, argv, options, long_options, (int *) 0);
      if (c == EOF)
        /* End of arguments, or "--" marker seen.  */
        break;
      else if (c == 1)
        /* An argument not starting with a dash.  */
        handle_non_switch_argument (optarg, env);
      else if (c == '?')
        /* Bad option.  We will print a usage message and die later.
           But continue to parse the other options so the user can
           see all he did wrong.  */
        bad = 1;
      else
        for (cs = switches; cs->c != '\0'; ++cs)
          if (cs->c == c)
            {
              /* Whether or not we will actually do anything with
                 this switch.  We test this individually inside the
                 switch below rather than just once outside it, so that
                 options which are to be ignored still consume args.  */
              int doit = !env || cs->env;

              switch (cs->type)
                {
                default:
                  abort ();

                case ignore:
                  break;

                case flag:
                case flag_off:
                  if (doit)
                    *(int *) cs->value_ptr = cs->type == flag;
                  break;

                case string:
                  if (!doit)
                    break;

                  if (optarg == 0)
                    optarg = cs->noarg_value;

                  sl = *(struct stringlist **) cs->value_ptr;
                  if (sl == 0)
                    {
                      sl = (struct stringlist *)
                        xmalloc (sizeof (struct stringlist));
                      sl->max = 5;
                      sl->idx = 0;
                      sl->list = (char **) xmalloc (5 * sizeof (char *));
                      *(struct stringlist **) cs->value_ptr = sl;
                    }
                  else if (sl->idx == sl->max - 1)
                    {
                      sl->max += 5;
                      sl->list = (char **)
                        xrealloc ((char *) sl->list,
                                  sl->max * sizeof (char *));
                    }
                  sl->list[sl->idx++] = optarg;
                  sl->list[sl->idx] = 0;
                  break;

                case positive_int:
                  if (optarg == 0 && argc > optind
                      && isdigit (argv[optind][0]))
                    optarg = argv[optind++];

                  if (!doit)
                    break;

                  if (optarg != 0)
                    {
                      int i = atoi (optarg);
                      if (i < 1)
                        {
                          if (doit)
                            error ("the `-%c' option requires a \
positive integral argument",
                                   cs->c);
                          bad = 1;
                        }
                      else
                        *(unsigned int *) cs->value_ptr = i;
                    }
                  else
                    *(unsigned int *) cs->value_ptr
                      = *(unsigned int *) cs->noarg_value;
                  break;

                case floating:
                  if (optarg == 0 && optind < argc
                      && (isdigit (argv[optind][0]) || argv[optind][0] == '.'))
                    optarg = argv[optind++];

                  if (doit)
                    *(double *) cs->value_ptr               
                      = (optarg != 0 ? atof (optarg)
                         : *(double *) cs->noarg_value);

                  break;
                }
            
              /* We've found the switch.  Stop looking.  */
              break;
            }
    }

  /* There are no more options according to getting getopt, but there may
     be some arguments left.  Since we have asked for non-option arguments
     to be returned in order, this only happens when there is a "--"
     argument to prevent later arguments from being options.  */
  while (optind < argc)
    handle_non_switch_argument (argv[optind++], env);


  if (!env && (bad || print_usage_flag))
    {
      /* Print a nice usage message.  */
      FILE *usageto;

      if (print_version_flag)
        print_version ();

      usageto = bad ? stderr : stdout;

      fprintf (usageto, "Usage: %s [options] [target] ...\n", program);

      fputs ("Options:\n", usageto);
      for (cs = switches; cs->c != '\0'; ++cs)
        {
          char buf[1024], shortarg[50], longarg[50], *p;

          if (cs->description[0] == '-')
            continue;

          switch (long_options[cs - switches].has_arg)
            {
            case no_argument:
              shortarg[0] = longarg[0] = '\0';
              break;
            case required_argument:
              sprintf (longarg, "=%s", cs->argdesc);
              sprintf (shortarg, " %s", cs->argdesc);
              break;
            case optional_argument:
              sprintf (longarg, "[=%s]", cs->argdesc);
              sprintf (shortarg, " [%s]", cs->argdesc);
              break;
            }

          p = buf;

          if (isalnum (cs->c))
            {
              sprintf (buf, "  -%c%s", cs->c, shortarg);
              p += strlen (p);
            }
          if (cs->long_name != 0)
            {
              unsigned int i;
              sprintf (p, "%s--%s%s",
                       !isalnum (cs->c) ? "  " : ", ",
                       cs->long_name, longarg);
              p += strlen (p);
              for (i = 0; i < (sizeof (long_option_aliases) /
                               sizeof (long_option_aliases[0]));
                   ++i)
                if (long_option_aliases[i].val == cs->c)
                  {
                    sprintf (p, ", --%s%s",
                             long_option_aliases[i].name, longarg);
                    p += strlen (p);
                  }
            }
          {
            const struct command_switch *ncs = cs;
            while ((++ncs)->c != '\0')
              if (ncs->description[0] == '-' &&
                  ncs->description[1] == cs->c)
                {
                  /* This is another switch that does the same
                     one as the one we are processing.  We want
                     to list them all together on one line.  */
                  sprintf (p, ", -%c%s", ncs->c, shortarg);
                  p += strlen (p);
                  if (ncs->long_name != 0)
                    {
                      sprintf (p, ", --%s%s", ncs->long_name, longarg);
                      p += strlen (p);
                    }
                }
          }

          if (p - buf > DESCRIPTION_COLUMN - 2)
            /* The list of option names is too long to fit on the same
               line with the description, leaving at least two spaces.
               Print it on its own line instead.  */
            {
              fprintf (usageto, "%s\n", buf);
              buf[0] = '\0';
            }

          fprintf (usageto, "%*s%s.\n",
                   - DESCRIPTION_COLUMN,
                   buf, cs->description);
        }

      die (bad ? 2 : 0);
    }
}

/* Decode switches from environment variable ENVAR (which is LEN chars long).
   We do this by chopping the value into a vector of words, prepending a
   dash to the first word if it lacks one, and passing the vector to
   decode_switches.  */

static void
decode_env_switches (envar, len)
     char *envar;
     unsigned int len;
{
  char *varref = (char *) alloca (2 + len + 2);
  char *value, *p;
  int argc;
  char **argv;

  /* Get the variable's value.  */
  varref[0] = '$';
  varref[1] = '(';
  bcopy (envar, &varref[2], len);
  varref[2 + len] = ')';
  varref[2 + len + 1] = '\0';
  value = variable_expand (varref);

  /* Skip whitespace, and check for an empty value.  */
  value = next_token (value);
  len = strlen (value);
  if (len == 0)
    return;

  /* Allocate a vector that is definitely big enough.  */
  argv = (char **) alloca ((1 + len + 1) * sizeof (char *));

  /* Allocate a buffer to copy the value into while we split it into words
     and unquote it.  We must use permanent storage for this because
     decode_switches may store pointers into the passed argument words.  */
  p = (char *) xmalloc (2 * len);

  /* getopt will look at the arguments starting at ARGV[1].
     Prepend a spacer word.  */
  argv[0] = 0;
  argc = 1;
  argv[argc] = p;
  while (*value != '\0')
    {
      if (*value == '\\')
        ++value;                /* Skip the backslash.  */
      else if (isblank (*value))
        {
          /* End of the word.  */
          *p++ = '\0';
          argv[++argc] = p;
          do
            ++value;
          while (isblank (*value));
          continue;
        }
      *p++ = *value++;
    }
  *p = '\0';
  argv[++argc] = 0;

  if (argc == 2 && argv[1][0] != '-')
    {
      /* There is just one word in the value, and it is not a switch.
         Either this is the single-word form and we should prepend a dash
         before calling decode_switches, or this is the multi-word form and
         there is no dash because it is a variable definition.  */
      struct variable *v;
      v = try_variable_definition ((char *) 0, 0, argv[1], o_command);
      if (v != 0)
        {
          /* It was indeed a variable definition, and now it has been
             processed.  There is nothing for decode_switches to do.
             Record a pointer to the variable for later use in
             define_makeflags.  */
          struct command_variable *cv
            = (struct command_variable *) xmalloc (sizeof (*cv));
          cv->variable = v;
          cv->next = command_variables;
          command_variables = cv;
          return;
        }

      /* It wasn't a variable definition, so it's some switches without a
         leading dash.  Add one and pass it along to decode_switches.  We
         need permanent storage for this in case decode_switches saves
         pointers into the value.  */
      argv[1] = concat ("-", argv[1], "");
    }

  /* Parse those words.  */
  decode_switches (argc, argv, 1);
}
\f
/* Quote the string IN so that it will be interpreted as a single word with
   no magic by the shell; if DOUBLE_DOLLARS is nonzero, also double dollar
   signs to avoid variable expansion in make itself.  Write the result into
   OUT, returning the address of the next character to be written.
   Allocating space for OUT twice the length of IN (thrice if
   DOUBLE_DOLLARS is nonzero) is always sufficient.  */

static char *
quote_as_word (out, in, double_dollars)
     char *out, *in;
     int double_dollars;
{
  while (*in != '\0')
    {
      if (index ("^;'\"*?[]$<>(){}|&~`\\ \t\r\n\f\v", *in) != 0)
        *out++ = '\\';
      if (double_dollars && *in == '$')
        *out++ = '$';
      *out++ = *in++;
    }

  return out;
}

/* Define the MAKEFLAGS and MFLAGS variables to reflect the settings of the
   command switches.  Include options with args if ALL is nonzero.
   Don't include options with the `no_makefile' flag set if MAKEFILE.  */

static void
define_makeflags (all, makefile)
     int all, makefile;
{
  static const char ref[] = "$(MAKEOVERRIDES)";
  static const char posixref[] = "$(-*-command-variables-*-)";
  register const struct command_switch *cs;
  char *flagstring;
  register char *p;
  unsigned int words;
  struct variable *v;

  /* We will construct a linked list of `struct flag's describing
     all the flags which need to go in MAKEFLAGS.  Then, once we
     know how many there are and their lengths, we can put them all
     together in a string.  */

  struct flag
    {
      struct flag *next;
      const struct command_switch *cs;
      char *arg;
    };
  struct flag *flags = 0;
  unsigned int flagslen = 0;
#define ADD_FLAG(ARG, LEN) \
  do {                                                                        \
    struct flag *new = (struct flag *) alloca (sizeof (struct flag));         \
    new->cs = cs;                                                             \
    new->arg = (ARG);                                                         \
    new->next = flags;                                                        \
    flags = new;                                                              \
    if (new->arg == 0)                                                        \
      ++flagslen;               /* Just a single flag letter.  */             \
    else                                                                      \
      flagslen += 1 + 1 + 1 + 1 + 3 * (LEN); /* " -x foo" */                  \
    if (!isalnum (cs->c))                                                     \
      /* This switch has no single-letter version, so we use the long.  */    \
      flagslen += 2 + strlen (cs->long_name);                                 \
  } while (0)

  for (cs = switches; cs->c != '\0'; ++cs)
    if (cs->toenv && (!makefile || !cs->no_makefile))
      switch (cs->type)
        {
        default:
          abort ();

        case ignore:
          break;

        case flag:
        case flag_off:
          if (!*(int *) cs->value_ptr == (cs->type == flag_off)
              && (cs->default_value == 0
                  || *(int *) cs->value_ptr != *(int *) cs->default_value))
            ADD_FLAG (0, 0);
          break;

        case positive_int:
          if (all)
            {
              if ((cs->default_value != 0
                   && (*(unsigned int *) cs->value_ptr
                       == *(unsigned int *) cs->default_value)))
                break;
              else if (cs->noarg_value != 0
                       && (*(unsigned int *) cs->value_ptr ==
                           *(unsigned int *) cs->noarg_value))
                ADD_FLAG ("", 0); /* Optional value omitted; see below.  */
              else if (cs->c == 'j')
                /* Special case for `-j'.  */
                ADD_FLAG ("1", 1);
              else
                {
                  char *buf = (char *) alloca (30);
                  sprintf (buf, "%u", *(unsigned int *) cs->value_ptr);
                  ADD_FLAG (buf, strlen (buf));
                }
            }
          break;

        case floating:
          if (all)
            {
              if (cs->default_value != 0
                  && (*(double *) cs->value_ptr
                      == *(double *) cs->default_value))
                break;
              else if (cs->noarg_value != 0
                       && (*(double *) cs->value_ptr
                           == *(double *) cs->noarg_value))
                ADD_FLAG ("", 0); /* Optional value omitted; see below.  */
              else
                {
                  char *buf = (char *) alloca (100);
                  sprintf (buf, "%g", *(double *) cs->value_ptr);
                  ADD_FLAG (buf, strlen (buf));
                }
            }
          break;

        case string:
          if (all)
            {
              struct stringlist *sl = *(struct stringlist **) cs->value_ptr;
              if (sl != 0)
                {
                  /* Add the elements in reverse order, because
                     all the flags get reversed below; and the order
                     matters for some switches (like -I).  */
                  register unsigned int i = sl->idx;
                  while (i-- > 0)
                    ADD_FLAG (sl->list[i], strlen (sl->list[i]));
                }
            }
          break;
        }

  flagslen += 4 + sizeof posixref; /* Four more for the possible " -- ".  */

#undef  ADD_FLAG

  /* Construct the value in FLAGSTRING.
     We allocate enough space for a preceding dash and trailing null.  */
  flagstring = (char *) alloca (1 + flagslen + 1);
  p = flagstring;
  words = 1;
  *p++ = '-';
  while (flags != 0)
    {
      /* Add the flag letter or name to the string.  */
      if (!isalnum (flags->cs->c))
        {
          *p++ = '-';
          strcpy (p, flags->cs->long_name);
          p += strlen (p);
        }
      else
        *p++ = flags->cs->c;
      if (flags->arg != 0)
        {
          /* A flag that takes an optional argument which in this case is
             omitted is specified by ARG being "".  We must distinguish
             because a following flag appended without an intervening " -"
             is considered the arg for the first.  */
          if (flags->arg[0] != '\0')
            {
              /* Add its argument too.  */
              *p++ = !isalnum (flags->cs->c) ? '=' : ' ';
              p = quote_as_word (p, flags->arg, 1);
            }
          ++words;
          /* Write a following space and dash, for the next flag.  */
          *p++ = ' ';
          *p++ = '-';
        }
      else if (!isalnum (flags->cs->c))
        {
          ++words;
          /* Long options must each go in their own word,
             so we write the following space and dash.  */
          *p++ = ' ';
          *p++ = '-';
        }
      flags = flags->next;
    }


  /* Define MFLAGS before appending variable definitions.  */

  if (p == &flagstring[1])
    /* No flags.  */
    flagstring[0] = '\0';
  else if (p[-1] == '-')
    /* Kill the final space and dash.  */
    p[-2] = '\0';
  else
    /* Terminate the string.  */
    *p = '\0';

  /* Since MFLAGS is not parsed for flags, there is no reason to
     override any makefile redefinition.  */
  (void) define_variable ("MFLAGS", 6, flagstring, o_env, 1);


  if (all && command_variables != 0)
    {
      /* Now write a reference to $(MAKEOVERRIDES), which contains all the
         command-line variable definitions.  */

      if (p == &flagstring[1])
        /* No flags written, so elide the leading dash already written.  */
        p = flagstring;
      else
        {
          /* Separate the variables from the switches with a "--" arg.  */
          if (p[-1] != '-')
            {
              /* We did not already write a trailing " -".  */
              *p++ = ' ';
              *p++ = '-';
            }
          /* There is a trailing " -"; fill it out to " -- ".  */
          *p++ = '-';
          *p++ = ' ';
        }

      /* Copy in the string.  */
      if (posix_pedantic)
        {
          bcopy (posixref, p, sizeof posixref - 1);
          p += sizeof posixref - 1;
        }
      else
        {
          bcopy (ref, p, sizeof ref - 1);
          p += sizeof ref - 1;
        }
    }
  else if (p == &flagstring[1])
    {
      words = 0;
      --p;
    }
  else if (p[-1] == '-')
    /* Kill the final space and dash.  */
    p -= 2;
  /* Terminate the string.  */
  *p = '\0';

  v = define_variable ("MAKEFLAGS", 9,
                       /* If there is just a single word of switches,
                          omit the leading dash unless it is a single
                          long option with two leading dashes.  */
                       &flagstring[(words == 1 && command_variables == 0
                                    && flagstring[1] != '-')
                                   ? 1 : 0],
                       /* This used to use o_env, but that lost when a
                          makefile defined MAKEFLAGS.  Makefiles set
                          MAKEFLAGS to add switches, but we still want
                          to redefine its value with the full set of
                          switches.  Of course, an override or command
                          definition will still take precedence.  */
                       o_file, 1);
  if (! all)
    /* The first time we are called, set MAKEFLAGS to always be exported.
       We should not do this again on the second call, because that is
       after reading makefiles which might have done `unexport MAKEFLAGS'. */
    v->export = v_export;
}
\f
/* Print version information.  */

static void
print_version ()
{
  static int printed_version = 0;

  char *precede = print_data_base_flag ? "# " : "";

  if (printed_version)
    /* Do it only once.  */
    return;

  printf ("%sGNU Make version %s", precede, version_string);
  if (remote_description != 0 && *remote_description != '\0')
    printf ("-%s", remote_description);

  printf (", by Richard Stallman and Roland McGrath.\n\
%sCopyright (C) 1988, 89, 90, 91, 92, 93, 94, 95 Free Software Foundation, Inc.\n\
%sThis is free software; see the source for copying conditions.\n\
%sThere is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A\n\
%sPARTICULAR PURPOSE.\n\n", precede, precede, precede, precede);

  printed_version = 1;

  /* Flush stdout so the user doesn't have to wait to see the
     version information while things are thought about.  */
  fflush (stdout);
}

/* Print a bunch of information about this and that.  */

static void
print_data_base ()
{
  extern char *ctime ();
  time_t when;

  when = time ((time_t *) 0);
  printf ("\n# Make data base, printed on %s", ctime (&when));

  print_variable_data_base ();
  print_dir_data_base ();
  print_rule_data_base ();
  print_file_data_base ();
  print_vpath_data_base ();

  when = time ((time_t *) 0);
  printf ("\n# Finished Make data base on %s\n", ctime (&when));
}
\f
/* Exit with STATUS, cleaning up as necessary.  */

void
die (status)
     int status;
{
  static char dying = 0;

  if (!dying)
    {
      int err;

      dying = 1;

      /* Try to move back to the original directory.  This is essential on
         MS-DOS (where there is really only one process), and on Unix it
         puts core files in the original directory instead of the -C
         directory.  */
      if (directory_before_chdir != 0)
        chdir (directory_before_chdir);

      if (print_version_flag)
        print_version ();

      /* Wait for children to die.  */
      for (err = status != 0; job_slots_used > 0; err = 0)
        reap_children (1, err);

      /* Remove the intermediate files.  */
      remove_intermediates (0);

      if (print_data_base_flag)
        print_data_base ();

      if (print_directory_flag)
        log_working_directory (0);
    }

  exit (status);
}
\f
/* Write a message indicating that we've just entered or
   left (according to ENTERING) the current directory.  */

static void
log_working_directory (entering)
     int entering;
{
  static int entered = 0;
  char *message = entering ? "Entering" : "Leaving";

  if (entering)
    entered = 1;
  else if (!entered)
    /* Don't print the leaving message if we
       haven't printed the entering message.  */
    return;

  if (print_data_base_flag)
    fputs ("# ", stdout);

  if (makelevel == 0)
    printf ("%s: %s ", program, message);
  else
    printf ("%s[%u]: %s ", program, makelevel, message);

  if (starting_directory == 0)
    puts ("an unknown directory");
  else
    printf ("directory `%s'\n", starting_directory);
}