n_shell_quote(): rewrite, tweak user-at-a-glance experience

[s-mailx.git] / make.rc

#@ make.rc can be used adjust the set of features, paths, etc.
#@ You should have read "INSTALL" first.
#@ Notes:
#@ . Specifying settings on the command line will take precedence over
#@   the variables in here (correctly triggering build updates as
#@   necessary, too).
#@ . Choosing one of the predefined CONFIG= sets overwrites a lot of
#@   items that can be set in here / from the command line.
#@ . This file is parsed by the shell: it is in sh(1), not in make(1)
#@   syntax.  Evaluation occurs *after* it has been read, so command
#@   line overwrites take effect.  To use multiline values, escape the
#@   newlines on any but the last line with a backslash, as in "LINE \".
#@   The parsing is sequential top-to-bottom (nonetheless) so that shell
#@   snippets in a value can refer only to stuff yet defined.
#@ . Boolean values can be set via 1/0, true/false, yes/no and on/off
#@   (case doesn't matter), other values result in an error.
#@ . However, the value "require" is also a true boolean, but will in
#@   addition cause configuration to fail if the requested feature is
#@   missing.  This special behaviour is only tested by a logical subset
#@   of feature tests.
#@ . You may NOT comment out anything in here -- if you want to disable
#@   a feature, set it to a false boolean.

## PATHS AND PROGRAMS ##

# General prefix where S-nail should be installed.
PREFIX=/usr/local

# Fine tune individual locations, normally under $PREFIX.
# . the place of the S-nail program.
BINDIR="${PREFIX}/bin"
# Only if WANT_DOTLOCK is enabled:
# . the place of the privilege-separated helper program.
LIBEXECDIR="${PREFIX}/libexec"
# . of the manual.
MANDIR="${PREFIX}/share/man"
# . of the exemplary resource file.
SYSCONFDIR="${PREFIX}/etc"

# This variable is prepended to all the paths from above at installation
# time; this feature can be used for, e.g., package building: if $PREFIX
# is "/usr/local", but $DESTDIR is set to "here", then S-nail will still
# think its $PREFIX is "/usr/local" whereis the build system will
# instead use "here/usr/local".
DESTDIR=

# Where the local mail system stores user mail (mbox) files.
MAILSPOOL=`\
   if [ -d /var/spool/mail ]; then \
      echo /var/spool/mail;\
   else \
      echo /var/mail;\
   fi`

## TODO In v15 we will have a clean separation in between options (OPT_) and
## TODO values (VAL_).  This is better than the current WANT_ and XYZ mess.
## TODO Start today with a few

# Path to the local MTA (Mail Transport Agent).
VAL_SENDMAIL=`\
   if [ -x /usr/bin/sendmail ]; then \
      echo /usr/bin/sendmail;\
   elif [ -x /usr/lib/sendmail ]; then \
      echo /usr/lib/sendmail;\
   else \
      echo /usr/sbin/sendmail;\
   fi`

# Today a lot of systems no longer use sendmail(1), but a different MTA.
# To ensure compatibility with sendmail(1), a system called
# mailwrapper(8) is often used, which selects the required service by
# looking at the name by which the program actually has been invoked.
# This variable can be used to adjust this name as necessary.
VAL_SENDMAIL_PROGNAME=sendmail

# Default *SHELL* (sh(1) path).
# Sometimes we simply invoke a command directly via execlp(2) instead of
# indirectly through *SHELL* -- in these cases execlp(2) may fallback to
# it's own builtin sh(1) path
VAL_SHELL=/bin/sh

# Some more default fallback values, some of which are standardized
# and (thus)/or documented in the manual (changes not reflected there!)
VAL_DEAD=~/dead.letter
VAL_EDITOR=ed
VAL_LISTER=ls
VAL_MAILRC=~/.mailrc
VAL_MBOX=~/.mbox
VAL_NETRC=~/.netrc
VAL_PAGER=more
VAL_TMPDIR=/tmp
VAL_VISUAL=vi

# The following tools may be provided a.k.a. overwritten,
# `command -v NAME` is used to query the utility otherwise:
#  MAKE=, STRIP=, awk=, cat=, chmod=, cp=, cmp=, cksum=,
#     grep=, mkdir=, mv=, rm=, sed=, sort=, tee=, tr=
# Usually in administrator paths:
#  chown= [WANT_DOTLOCK]
# Note that awk(1), rm(1) and tr(1) are needed before this file is read,
# all other utilities will be checked afterwards only.  For
# cross-compilation setting MAKE= and STRIP= may be necessary.  Due to
# the evaluation order of the build system all those programs are
# usually needed, but by setting any of the variables to true(1), as in
# chown=/usr/bin/true, availability of unneeded programs can be faked.
# We require uname(1) -s, command(1) -v, echo(1), etc.
# uname(1) can be circumvented by setting $OS.

## FEATURE SET ##

# Shall S-nail try to automatically detect a compiler and provide a set
# of known-good compiler flags?  If so additions may still be provided
# by setting $ADDCFLAGS and $ADDLDFLAGS to whatever is desired.
# Thus: set this to false and use your normal $CC / $CFLAGS / $LDFLAGS,
# set this to true and pass additional flags via ADDCFLAGS / ADDLDFLAGS:
#     $ make ADDCFLAGS=-std=c99 install
# Whatever you do, the configuration is fixated and updates will force
# rebuilds.  And far below in this file there is WANT_FORCED_STACKPROT,
# too, which can be used to cause injection of stack protectors.
WANT_AUTOCC=yes

# It is possible to compile S-nail as a "single-source", meaning that
# all source files are injected into a single compilation unit, which is
# then compiled.  This allows the compiler to perform much more
# optimizations, and also reduces the management overhead that is used
# for / needed by the linker.
WANT_AMALGAMATION=no

# Character set conversion enables reading and sending of mails in
# multiple character sets through usage of the iconv(3) library.  Please
# read the manual section "Character sets" for the complete picture.
# This should usually be enabled; it can be "require"d.
WANT_ICONV=yes

# Major switch to toggle *all* network related protocols
# (POP3,SMTP) and related/dependent stuff (GSS-API,SSL);
# can be "require"d.
WANT_SOCKETS=yes

# If $WANT_SOCKETS: support for Secure Socket Layer (Transport Layer
# Security, TLS), i.e., encrypted socket connections; can be "require"d.
# This needs the OpenSSL libraries (<http://www.openssl.org>).
WANT_SSL=yes

# If $WANT_SSL: shall S-nail (try to) use mechanisms to support more
# digest and cipher algorithms than the few that are documented?  For
# S/MIME *smime-cipher* for example this will cause
# EVP_get_cipherbyname(3) to be tried shall the (S-nail-) builtin
# knowledge not suffice to understand the user request.  Will create
# a large statically linked binary; dynamically linked the costs only
# arise once the extended lookup is actually needed (the first time).
# This can be "require"d.
WANT_SSL_ALL_ALGORITHMS=yes

# If $WANT_SOCKETS: support for SMTP protocol?
# (Directly sending mails over the network)  Can be "require"d.
WANT_SMTP=yes

# If $WANT_SOCKETS: support for POP3 protocol?
# (Download of mails via POP protocol)  Can be "require"d.
WANT_POP3=yes

# If $WANT_SOCKETS: support for GSS-API (Generic Security Services
# Application Programming Interface) based authentication, e.g.,
# Kerberos v5?  Available for SMTP; can be "require"d.
WANT_GSSAPI=yes

# Enabling the MD5 message digest adds support for several
# authentication possibilities: POP3 (APOP), SMTP (CRAM-MD5).
# If you don't need those, you may turn them off by excluding MD5.
WANT_MD5=yes

# If $WANT_SOCKETS: support for parsing of user and password credentials
# from the ~/.netrc file ($NETRC; see *netrc-lookup* manual entry).
WANT_NETRC=yes

# If $WANT_SOCKETS: passwords can also be looked up through an external
# "agent" in order to allow for encrypted password storage (see
# *agent-shell-lookup*).
WANT_AGENT=yes

# IDNA (internationalized domain names for applications) offers users
# the possibility to use domain names in their native language, i.e., to
# use non-US-ASCII content, as in, e.g., <www.räksmörgåsa.example>,
# which the IDNA algorithm would convert to
# <www.xn--rksmrgsa-0zap8p.example>.  :)  This either needs idnkit
# (<https://www.nic.ad.jp/ja/idn/idnkit/download/>) or the GNU Libidn
# library (<https://www.gnu.org/software/libidn/>).  It can be
# "require"d.
WANT_IDNA=yes

# IMAP-style SEARCH expressions can be supported.  This addressing mode
# is available with all types of folders; for folders not located on
# IMAP servers, or for servers unable to execute the SEARCH command, the
# search is performed locally.
WANT_IMAP_SEARCH=yes

# Regular expression (re_format(7)) support for searches, conditional
# expressions etc., we use the extended ones, then; can be "require"d.
WANT_REGEX=yes

# Line editing and -history (manual "On terminal and line editor").
# One may choose in between different line editors.  Note that (1) only
# the builtin MLE (may) map(s) 1:1 to the behaviour as is documented in
# the manual and (2) these are tested in the shown order:
# . WANT_READLINE
#   The GNU readline(3) compatible interface; can be "require"d.
# . WANT_MLE
#   If ISO C (ISO/IEC 9899:1990/Amendment 1:1995) is supported on the
#   system then our builtin MLE (Mailx-Line-Editor) version can be used.
#   An enabled & available WANT_TERMCAP may affect and improve the MLE.
#   Can be "require"d.
WANT_READLINE=no
WANT_MLE=yes
# All line editors optionally support history management.
WANT_HISTORY=yes
# The MLE optionally supports `(un)?bind'ing of key sequences
WANT_KEY_BINDINGS=yes

# Use termcap(5) for terminal control; can be "require"d.
# Today most environments ship a termcap(5) that in fact is part of
# terminfo(5), and acts as a converting wrapper for this library.
# To avoid this redundancy we also support terminfo(5), and use it
# instead if we find it (assuming that termcap(5) is a stub, then).
# Note that terminfo(5) offers access to more key sequences, e.g.,
# kLFT5, for which no termcap(5) entry exists.
# terminfo(5) support can (thus) be "require"d.
WANT_TERMCAP=yes
WANT_TERMCAP_PREFER_TERMINFO=yes

# Enable the `errors' command; S-nail is a console-based application and
# thus errors may fly by pretty fast as other operations are in
# progress; or $PAGERs are started and clear errors off the screen.  If
# enabled errors are duplicated as they happen and the `errors' command
# will show them when asked to.
WANT_ERRORS=yes

# Interaction with a spam email filter is possible.
# Refer to all commands and variables with a "spam" prefix, and
# see the manual example section "Handling spam".
# . WANT_SPAM_SPAMC:
#   Support for interaction with spamassassin(1)s spamc(1).
# . WANT_SPAM_SPAMD:
#   Direct communication with spamassassin(1)s spamd(1).
#   Needs unix(4) domain sockets (checked).  Can be "require"d.
# . WANT_SPAM_FILTER:
#   Generic filter hook which can be used with e.g. bogofilter(1)
#   and sylfilter(1): see documentation for the *spam-filter-**
#   variables for expected application behaviour.
WANT_SPAM_SPAMC=no
WANT_SPAM_SPAMD=no
WANT_SPAM_FILTER=yes

# If given an optional argument the `help' command will print a help
# string only for the mentioned command; those strings take up space and
# so one may disable this feature.
WANT_DOCSTRINGS=yes

# A simple line-based quoting mechanism can be made available via the
# *quote-fold* mechanism.  This will be turned off automatically if the
# required character classification is not available on the host.
# TODO shouldn't wrap lines when only WS or a NL-escaping \ follows
WANT_QUOTE_FOLD=yes

# We do have a very primitive HTML tagsoup filter which can be used to
# convert HTML to plain text for display purposes.  If enabled it'll be
# used for all MIME types which have the @h@ or @H@ type markers (more
# on this in the manual section "THE mime.types FILES").  And which
# don't have any user defined MIME type handler, of course.
WANT_FILTER_HTML_TAGSOUP=yes

# A simple form of coloured output can optionally be produced.
WANT_COLOUR=yes

# File dotlocking is performed for "system mailbox" (%[USER] and
# %:ANYFILE) MBOX files: when synchronizing any such FILE a FILE.lock
# file will be created in the directory of FILE, for the duration of the
# synchronization.
# Set WANT_DOTLOCK to support this traditional mail spool file locking.
# MAILSPOOL(s) where normal system mailboxes reside are usually not
# writable by normal users, except that a user may read and write his
# own mailbox.  But this means that a program run by the user cannot
# create a .lock file!  The solution is to install a privilege-separated
# mini-program that has the sole purpose and functionality of managing
# the dotlock file in such situations -- and only then, as a last
# ressort.  Our small helper will be installed in LIBEXECDIR, SETUID to
# the PRIVSEP_USER (usually root).  With it dotlock files can be created
# for any mailbox for which the invoking user has read (or read-write)
# permissions, and under the UID and GID of the mailbox itself!
# The actual installation make targets will require the chown(1) program
# (as above) and require sufficient privileges to SETUID to PRIVSEP_USER.
# WANT_DOTLOCK can be "require"d.
WANT_DOTLOCK=yes
PRIVSEP_USER=root

##  --  >8  --  8<  --  ##
## Normal users should not need to read any further

## PATHS AND PROGRAMS, DEVELOPMENT ##

# To ease the life of forkers and packagers "our" name can be changed.
# The name is build by concatenating $SID and $NAIL, i.e.,
# $(SID)$(NAIL).  Note that the final string must be longer than two
# characters and may not contain any whitespace.
SID=s-
NAIL=nail

# The name of the exemplary resource template.
# Note 1: it's not overwritten by "make install" if it yet exists!
SYSCONFRC="${SID}${NAIL}.rc"

## FEATURE SET, DEVELOPMENT ##

# Use debug compiler flags, enable some additional commands and code
# assertions.  Note that setting this also enables our own memory
# canaries, which require a rather large amount of runtime memory, and
# forcefully disables alloca(3) stack memory usage (see $WANT_NOALLOCA
# below), so as to be able to track usage of "stack memory" via our
# memory canaries.
WANT_DEBUG=no

# Experimental code etc.
# Note: this will be forcefully set (again) if $WANT_DEBUG=yes.
WANT_DEVEL=no

# We use the crypto libraries' MD5 implementation if possible, unless..
WANT_NOEXTMD5=no

# The codebase makes a lot of use of alloca(3), and this will remain
# since S-nail will continue to be compliant to ISO C89, which has no
# variable ("flexible", sigh) arrays, etc.  For testing purposes it is
# however nice to use the much slower normal S-nail heap memory
# allocator instead.
# Note: this will be forcefully set (again) if $WANT_DEBUG=yes.
WANT_NOALLOCA="${WANT_DEBUG}"

# If $WANT_DEBUG is true we'll use a simple memory wrapper with
# canaries.  This interferes with memory debuggers like valgrind(1) or
# the LLVM -fsanitize stuff.  Enable this to not use our wrapper.
WANT_NOMEMDBG=no

# Our functions are instrumented with Not-Yet-Dead chirps, which print
# a function call trace when the program crashes.  Whereas NYD will be
# used automatically when either of WANT_DEBUG and WANT_DEVEL is
# defined, an extended level of NYD is compiled in only on explicit
# request.
# TODO Separation in between NYD and NYD2 not yet fully done.
WANT_NYD2=no

# With $WANT_AUTOCC we will use stack protector guards shall the
# detected compiler support them; this goes in line with our own (heap)
# memory canaries and will detect buffer overflows.  It is usually only
# useful during development, i.e., in a debug environment that tests all
# aspects of a program.
WANT_FORCED_STACKPROT=`\
   if feat_yes DEVEL || feat_yes DEBUG; then \
      echo yes;\
   else \
      echo no;\
   fi`

# vim:set tw=72: s-it-mode