1 GNU make NEWS -*-indented-text-*-
2 History of user-visible changes.
5 Copyright (C) 1992,93,94,95,96,97,98,1999 Free Software Foundation, Inc.
6 See the end for copying conditions.
8 All changes mentioned here are more fully described in the GNU make
9 manual, which is contained in this distribution as the file make.texinfo.
11 Please send GNU make bug reports to bug-make@gnu.org.
15 * Two new functions, $(error ...) and $(warning ...) are available. The
16 former will cause make to fail and exit immediately upon expansion of
17 the function, with the text provided as the error message. The latter
18 causes the text provided to be printed as a warning message, but make
21 * A new function $(call ...) is available. This allows users to create
22 their own parameterized macros and invoke them later. Original
23 implementation of this function was provided by Han-Wen Nienhuys
26 * A new function $(if ...) is available. It provides if-then-else
27 capabilities in a builtin function. Original implementation of this
28 function was provided by Han-Wen Nienhuys <hanwen@cs.uu.nl>.
30 * Make defines a new variable, .LIBPATTERNS. This variable controls how
31 library dependency expansion (dependencies like ``-lfoo'') is performed.
33 * Make accepts CRLF sequences as well as traditional LF, for
34 compatibility with makefiles created on other operating systems.
36 * Make accepts a new option: -R, or --no-builtin-variables. This option
37 disables the definition of the rule-specific builtin variables (CC,
38 LD, AR, etc.). Specifying this option forces -r (--no-builtin-rules)
41 * A "job server" feature, suggested by Howard Chu <hyc@highlandsun.com>.
43 On systems that support POSIX pipe(2) semantics, GNU make can now pass
44 -jN options to submakes rather than forcing them all to use -j1. The
45 top make and all its sub-make processes use a pipe to communicate with
46 each other to ensure that no more than N jobs are started across all
47 makes. To get the old behavior of -j back, you can configure make
48 with the --disable-job-server option.
50 * The confusing term "dependency" has been replaced by the more accurate
51 and standard term "prerequisite", both in the manual and in all GNU make
54 * GNU make supports the "big archive" library format introduced in AIX 4.3.
56 * GNU make supports large files on AIX, HP-UX, and IRIX. These changes
57 were provided by Paul Eggert <eggert@twinsun.com>. (Large file
58 support for Solaris and Linux was introduced in 3.77, but the
59 configuration had issues: these have also been resolved).
61 * The Windows 95/98/NT (W32) version of GNU make now has native support
62 for the Cygnus Cygwin release B20.1 shell (bash).
64 * The GNU make regression test suite, long available separately "under
65 the table", has been integrated into the release. You can invoke it
66 by running "make check" in the distribution. Note that it requires
67 Perl (either Perl 4 or Perl 5) to run.
71 * Implement BSD make's "?=" variable assignment operator. The variable
72 is assigned the specified value only if that variable is not already
75 * Make defines a new variable, "CURDIR", to contain the current working
76 directory (after the -C option, if any, has been processed).
77 Modifying this variable has no effect on the operation of make.
79 * Make defines a new default RCS rule, for new-style master file
80 storage: ``% :: RCS/%'' (note no ``,v'' suffix).
82 Make defines new default rules for DOS-style C++ file naming
83 conventions, with ``.cpp'' suffixes. All the same rules as for
84 ``.cc'' and ``.C'' suffixes are provided, along with LINK.cpp and
85 COMPILE.cpp macros (which default to the same value as LINK.cc and
86 COMPILE.cc). Note CPPFLAGS is still C preprocessor flags! You should
87 use CXXFLAGS to change C++ compiler flags.
89 * A new feature, "target-specific variable values", has been added.
90 This is a large change so please see the appropriate sections of the
91 manual for full details. Briefly, syntax like this:
93 TARGET: VARIABLE = VALUE
95 defines VARIABLE as VALUE within the context of TARGET. This is
96 similar to SunOS make's "TARGET := VARIABLE = VALUE" feature. Note
97 that the assignment may be of any type, not just recursive, and that
98 the override keyword is available.
100 COMPATIBILITY: This new syntax means that if you have any rules where
101 the first or second dependency has an equal sign (=) in its name,
102 you'll have to escape them with a backslash: "foo : bar\=baz".
103 Further, if you have any dependencies which already contain "\=",
104 you'll have to escape both of them: "foo : bar\\\=baz".
106 * A new appendix listing the most common error and warning messages
107 generated by GNU make, with some explanation, has been added to the
108 GNU make User's Manual.
110 * Updates to the GNU make Customs library support (see README.customs).
112 * Updates to the Windows 95/NT port from Rob Tulloh (see README.W32),
113 and to the DOS port from Eli Zaretski (see README.DOS).
117 * Small (but serious) bug fix. Quick rollout to get into the GNU source CD.
121 * GNU make now uses automake to control Makefile.in generation. This
122 should make it more consistent with the GNU standards.
124 * VPATH functionality has been changed to incorporate the VPATH+ patch,
125 previously maintained by Paul Smith <psmith@baynetworks.com>. See the
128 * Make defines a new variable, `MAKECMDGOALS', to contain the goals that
129 were specified on the command line, if any. Modifying this variable
130 has no effect on the operation of make.
132 * A new function, `$(wordlist S,E,TEXT)', is available: it returns a
133 list of words from number S to number E (inclusive) of TEXT.
135 * Instead of an error, detection of future modification times gives a
136 warning and continues. The warning is repeated just before GNU make
137 exits, so it is less likely to be lost.
139 * Fix the $(basename) and $(suffix) functions so they only operate on
140 the last filename, not the entire string:
142 Command Old Result New Result
143 ------- ---------- ----------
145 $(basename a.b/c) a a.b/c
147 $(suffix a.b/c) b/c <empty>
149 * The $(strip) function now removes newlines as well as TABs and spaces.
151 * The $(shell) function now changes CRLF (\r\n) pairs to a space as well
154 * Updates to the Windows 95/NT port from Rob Tulloh (see README.W32).
156 * Eli Zaretskii has updated the port to 32-bit protected mode on MSDOS
157 and MS-Windows, building with the DJGPP v2 port of GNU C/C++ compiler
158 and utilities. See README.DOS for details, and direct all questions
159 concerning this port to Eli Zaretskii <eliz@is.elta.co.il> or DJ
160 Delorie <dj@delorie.com>.
162 * John W. Eaton has updated the VMS port to support libraries and VPATH.
166 * The directory messages printed by `-w' and implicitly in sub-makes,
167 are now omitted if Make runs no commands and has no other messages to print.
169 * Make now detects files that for whatever reason have modification times
170 in the future and gives an error. Files with such impossible timestamps
171 can result from unsynchronized clocks, or archived distributions
172 containing bogus timestamps; they confuse Make's dependency engine
175 * The new directive `sinclude' is now recognized as another name for
176 `-include', for compatibility with some other Makes.
178 * Aaron Digulla has contributed a port to AmigaDOS. See README.Amiga for
179 details, and direct all Amiga-related questions to <digulla@fh-konstanz.de>.
181 * Rob Tulloh of Tivoli Systems has contributed a port to Windows NT or 95.
182 See README.W32 for details, and direct all Windows-related questions to
183 <rob_tulloh@tivoli.com>.
187 * Converted to use Autoconf version 2, so `configure' has some new options.
188 See INSTALL for details.
190 * You can now send a SIGUSR1 signal to Make to toggle printing of debugging
191 output enabled by -d, at any time during the run.
195 * DJ Delorie has ported Make to MS-DOS using the GO32 extender.
196 He is maintaining the DOS port, not the GNU Make maintainer;
197 please direct bugs and questions for DOS to <djgpp@sun.soe.clarkson.edu>.
198 MS-DOS binaries are available for FTP from ftp.simtel.net in
199 /pub/simtelnet/gnu/djgpp/.
201 * The `MAKEFLAGS' variable (in the environment or in a makefile) can now
202 contain variable definitions itself; these are treated just like
203 command-line variable definitions. Make will automatically insert any
204 variable definitions from the environment value of `MAKEFLAGS' or from
205 the command line, into the `MAKEFLAGS' value exported to children. The
206 `MAKEOVERRIDES' variable previously included in the value of `$(MAKE)'
207 for sub-makes is now included in `MAKEFLAGS' instead. As before, you can
208 reset `MAKEOVERRIDES' in your makefile to avoid putting all the variables
209 in the environment when its size is limited.
211 * If `.DELETE_ON_ERROR' appears as a target, Make will delete the target of
212 a rule if it has changed when its commands exit with a nonzero status,
213 just as when the commands get a signal.
215 * The automatic variable `$+' is new. It lists all the dependencies like
216 `$^', but preserves duplicates listed in the makefile. This is useful
217 for linking rules, where library files sometimes need to be listed twice
220 * You can now specify the `.IGNORE' and `.SILENT' special targets with
221 dependencies to limit their effects to those files. If a file appears as
222 a dependency of `.IGNORE', then errors will be ignored while running the
223 commands to update that file. Likewise if a file appears as a dependency
224 of `.SILENT', then the commands to update that file will not be printed
225 before they are run. (This change was made to conform to POSIX.2.)
229 * The automatic variables `$(@D)', `$(%D)', `$(*D)', `$(<D)', `$(?D)', and
230 `$(^D)' now omit the trailing slash from the directory name. (This change
231 was made to comply with POSIX.2.)
233 * The source distribution now includes the Info files for the Make manual.
234 There is no longer a separate distribution containing Info and DVI files.
236 * You can now set the variables `binprefix' and/or `manprefix' in
237 Makefile.in (or on the command line when installing) to install GNU make
238 under a name other than `make' (i.e., ``make binprefix=g install''
239 installs GNU make as `gmake').
241 * The built-in Texinfo rules use the new variables `TEXI2DVI_FLAGS' for
242 flags to the `texi2dvi' script, and `MAKEINFO_FLAGS' for flags to the
245 * The exit status of Make when it runs into errors is now 2 instead of 1.
246 The exit status is 1 only when using -q and some target is not up to date.
247 (This change was made to comply with POSIX.2.)
251 * It is no longer a fatal error to have a NUL character in a makefile.
252 You should never put a NUL in a makefile because it can have strange
253 results, but otherwise empty lines full of NULs (such as produced by
254 the `xmkmf' program) will always work fine.
256 * The error messages for nonexistent included makefiles now refer to the
257 makefile name and line number where the `include' appeared, so Emacs's
258 C-x ` command takes you there (in case it's a typo you need to fix).
262 * Implicit rule search for archive member references is now done in the
263 opposite order from previous versions: the whole target name `LIB(MEM)'
264 first, and just the member name and parentheses `(MEM)' second.
266 * Make now gives an error for an unterminated variable or function reference.
267 For example, `$(foo' with no matching `)' or `${bar' with no matching `}'.
269 * The new default variable `MAKE_VERSION' gives the version number of
270 Make, and a string describing the remote job support compiled in (if any).
271 Thus the value (in this release) is something like `3.69' or `3.69-Customs'.
273 * Commands in an invocation of the `shell' function are no longer run with
274 a modified environment like target commands are. As in versions before
275 3.68, they now run with the environment that `make' started with. We
276 have reversed the change made in version 3.68 because it turned out to
277 cause a paradoxical situation in cases like:
279 export variable = $(shell echo value)
281 When Make attempted to put this variable in the environment for a target
282 command, it would try expand the value by running the shell command
283 `echo value'. In version 3.68, because it constructed an environment
284 for that shell command in the same way, Make would begin to go into an
285 infinite loop and then get a fatal error when it detected the loop.
287 * The commands given for `.DEFAULT' are now used for phony targets with no
292 * You can list several archive member names inside parenthesis:
293 `lib(mem1 mem2 mem3)' is equivalent to `lib(mem1) lib(mem2) lib(mem3)'.
295 * You can use wildcards inside archive member references. For example,
296 `lib(*.o)' expands to all existing members of `lib' whose names end in
297 `.o' (e.g. `lib(a.o) lib(b.o)'); `*.a(*.o)' expands to all such members
298 of all existing files whose names end in `.a' (e.g. `foo.a(a.o)
299 foo.a(b.o) bar.a(c.o) bar.a(d.o)'.
301 * A suffix rule `.X.a' now produces two pattern rules:
302 (%.o): %.X # Previous versions produced only this.
303 %.a: %.X # Now produces this as well, just like other suffixes.
305 * The new flag `--warn-undefined-variables' says to issue a warning message
306 whenever Make expands a reference to an undefined variable.
308 * The new `-include' directive is just like `include' except that there is
309 no error (not even a warning) for a nonexistent makefile.
311 * Commands in an invocation of the `shell' function are now run with a
312 modified environment like target commands are, so you can use `export' et
313 al to set up variables for them. They used to run with the environment
314 that `make' started with.
318 * `make --version' (or `make -v') now exits immediately after printing
323 * Make now supports long-named members in `ar' archive files.
327 * Make now supports the `+=' syntax for a variable definition which appends
328 to the variable's previous value. See the section `Appending More Text
329 to Variables' in the manual for full details.
331 * The new option `--no-print-directory' inhibits the `-w' or
332 `--print-directory' feature. Make turns on `--print-directory'
333 automatically if you use `-C' or `--directory', and in sub-makes; some
334 users have found this behavior undesirable.
336 * The built-in implicit rules now support the alternative extension
337 `.txinfo' for Texinfo files, just like `.texinfo' and `.texi'.
341 * Make now uses a standard GNU `configure' script. See the new file
342 INSTALL for the new (and much simpler) installation procedure.
344 * There is now a shell script to build Make the first time, if you have no
345 other `make' program. `build.sh' is created by `configure'; see README.
347 * GNU Make now completely conforms to the POSIX.2 specification for `make'.
349 * Elements of the `$^' and `$?' automatic variables that are archive
350 member references now list only the member name, as in Unix and POSIX.2.
352 * You should no longer ever need to specify the `-w' switch, which prints
353 the current directory before and after Make runs. The `-C' switch to
354 change directory, and recursive use of Make, now set `-w' automatically.
356 * Multiple double-colon rules for the same target will no longer have their
357 commands run simultaneously under -j, as this could result in the two
358 commands trying to change the file at the same time and interfering with
361 * The `SHELL' variable is now never taken from the environment.
362 Each makefile that wants a shell other than the default (/bin/sh) must
363 set SHELL itself. SHELL is always exported to child processes.
364 This change was made for compatibility with POSIX.2.
366 * Make now accepts long options. There is now an informative usage message
367 that tells you what all the options are and what they do. Try `make --help'.
369 * There are two new directives: `export' and `unexport'. All variables are
370 no longer automatically put into the environments of the commands that
371 Make runs. Instead, only variables specified on the command line or in
372 the environment are exported by default. To export others, use:
374 or you can define variables with:
375 export VARIABLE = VALUE
377 export VARIABLE := VALUE
381 .EXPORT_ALL_VARIABLES:
382 to get the old behavior. See the node `Variables/Recursion' in the manual
383 for a full description.
385 * The commands from the `.DEFAULT' special target are only applied to
386 targets which have no rules at all, not all targets with no commands.
387 This change was made for compatibility with Unix make.
389 * All fatal error messages now contain `***', so they are easy to find in
392 * Dependency file names like `-lNAME' are now replaced with the actual file
393 name found, as with files found by normal directory search (VPATH).
394 The library file `libNAME.a' may now be found in the current directory,
395 which is checked before VPATH; the standard set of directories (/lib,
396 /usr/lib, /usr/local/lib) is now checked last.
397 See the node `Libraries/Search' in the manual for full details.
399 * A single `include' directive can now specify more than one makefile to
402 You can also use shell file name patterns in an `include' directive:
405 * The default directories to search for included makefiles, and for
406 libraries specified with `-lNAME', are now set by configuration.
408 * You can now use blanks as well as colons to separate the directories in a
409 search path for the `vpath' directive or the `VPATH' variable.
411 * You can now use variables and functions in the left hand side of a
412 variable assignment, as in "$(foo)bar = value".
414 * The `MAKE' variable is always defined as `$(MAKE_COMMAND) $(MAKEOVERRIDES)'.
415 The `MAKE_COMMAND' variable is now defined to the name with which make
418 * The built-in rules for C++ compilation now use the variables `$(CXX)' and
419 `$(CXXFLAGS)' instead of `$(C++)' and `$(C++FLAGS)'. The old names had
420 problems with shells that cannot have `+' in environment variable names.
422 * The value of a recursively expanded variable is now expanded when putting
423 it into the environment for child processes. This change was made for
424 compatibility with Unix make.
426 * A rule with no targets before the `:' is now accepted and ignored.
427 This change was made for compatibility with SunOS 4 make.
428 We do not recommend that you write your makefiles to take advantage of this.
430 * The `-I' switch can now be used in MAKEFLAGS, and are put there
431 automatically just like other switches.
435 * Built-in rules for C++ source files with the `.C' suffix.
436 We still recommend that you use `.cc' instead.
438 * If commands are given too many times for a single target,
439 the last set given is used, and a warning message is printed.
441 * Error messages about makefiles are in standard GNU error format,
442 so C-x ` in Emacs works on them.
444 * Dependencies of pattern rules which contain no % need not actually exist
445 if they can be created (just like dependencies which do have a %).
449 * A message is always printed when Make decides there is nothing to be done.
450 It used to be that no message was printed for top-level phony targets
451 (because "`phony' is up to date" isn't quite right). Now a different
452 message "Nothing to be done for `phony'" is printed in that case.
454 * Archives on AIX now supposedly work.
456 * When the commands specified for .DEFAULT are used to update a target,
457 the $< automatic variable is given the same value as $@ for that target.
458 This is how Unix make behaves, and this behavior is mandated by POSIX.2.
462 * The -n, -q, and -t options are not put in the `MAKEFLAGS' and `MFLAG'
463 variables while remaking makefiles, so recursive makes done while remaking
464 makefiles will behave properly.
466 * If the special target `.NOEXPORT' is specified in a makefile,
467 only variables that came from the environment and variables
468 defined on the command line are exported.
472 * Suffix rules may have dependencies (which are ignored).
476 * Dependencies of the form `-lLIB' are searched for as /usr/local/lib/libLIB.a
477 as well as libLIB.a in /usr/lib, /lib, the current directory, and VPATH.
481 * There is now a Unix man page for GNU Make. It is certainly not a replacement
482 for the Texinfo manual, but it documents the basic functionality and the
483 switches. For full documentation, you should still read the Texinfo manual.
484 Thanks to Dennis Morse of Stanford University for contributing the initial
487 * Variables which are defined by default (e.g., `CC') will no longer be put
488 into the environment for child processes. (If these variables are reset by the
489 environment, makefiles, or the command line, they will still go into the
492 * Makefiles which have commands but no dependencies (and thus are always
493 considered out of date and in need of remaking), will not be remade (if they
494 were being remade only because they were makefiles). This means that GNU
495 Make will no longer go into an infinite loop when fed the makefiles that
496 `imake' (necessary to build X Windows) produces.
498 * There is no longer a warning for using the `vpath' directive with an explicit
499 pathname (instead of a `%' pattern).
503 * When removing intermediate files, only one `rm' command line is printed,
504 listing all file names.
506 * There are now automatic variables `$(^D)', `$(^F)', `$(?D)', and `$(?F)'.
507 These are the directory-only and file-only versions of `$^' and `$?'.
509 * Library dependencies given as `-lNAME' will use "libNAME.a" in the current
510 directory if it exists.
512 * The automatic variable `$($/)' is no longer defined.
514 * Leading `+' characters on a command line make that line be executed even
515 under -n, -t, or -q (as if the line contained `$(MAKE)').
517 * For command lines containing `$(MAKE)', `${MAKE}', or leading `+' characters,
518 only those lines are executed, not their entire rules.
519 (This is how Unix make behaves for lines containing `$(MAKE)' or `${MAKE}'.)
523 * Filenames in rules will now have ~ and ~USER expanded.
525 * The `-p' output has been changed so it can be used as a makefile.
526 (All information that isn't specified by makefiles is prefaced with comment
531 * The % character can be quoted with backslash in implicit pattern rules,
532 static pattern rules, `vpath' directives, and `patsubst', `filter', and
533 `filter-out' functions. A warning is issued if a `vpath' directive's
534 pattern contains no %.
536 * The `wildcard' variable expansion function now expands ~ and ~USER.
538 * Messages indicating failed commands now contain the target name:
539 make: *** [target] Error 1
541 * The `-p' output format has been changed somewhat to look more like
542 makefile rules and to give all information that Make has about files.
548 * The `-l' switch with no argument removes any previous load-average limit.
550 * When the `-w' switch is in effect, and Make has updated makefiles,
551 it will write a `Leaving directory' messagfe before re-executing itself.
552 This makes the `directory change tracking' changes to Emacs's compilation
553 commands work properly.
557 * The automatic variable `$*' is now defined for explicit rules,
558 as it is in Unix make.
562 * The `-j' switch is now put in the MAKEFLAGS and MFLAGS variables when
563 specified without an argument (indicating infinite jobs).
564 The `-l' switch is not always put in the MAKEFLAGS and MFLAGS variables.
566 * Make no longer checks hashed directories after running commands.
567 The behavior implemented in 3.41 caused too much slowdown.
571 * A dependency is NOT considered newer than its dependent if
572 they have the same modification time. The behavior implemented
573 in 3.43 conflicts with RCS.
577 * Dependency loops are no longer fatal errors.
579 * A dependency is considered newer than its dependent if
580 they have the same modification time.
584 * The variables F77 and F77FLAGS are now set by default to $(FC) and
585 $(FFLAGS). Makefiles designed for System V make may use these variables in
586 explicit rules and expect them to be set. Unfortunately, there is no way to
587 make setting these affect the Fortran implicit rules unless FC and FFLAGS
588 are not used (and these are used by BSD make).
592 * Make now checks to see if its hashed directories are changed by commands.
593 Other makes that hash directories (Sun, 4.3 BSD) don't do this.
597 * The `shell' function no longer captures standard error output.
601 * A file beginning with a dot can be the default target if it also contains
602 a slash (e.g., `../bin/foo'). (Unix make allows this as well.)
606 * Archive member names are truncated to 15 characters.
608 * Yet more USG stuff.
610 * Minimal support for Microport System V (a 16-bit machine and a
611 brain-damaged compiler). This has even lower priority than other USG
612 support, so if it gets beyond trivial, I will take it out completely.
614 * Revamped default implicit rules (not much visible change).
616 * The -d and -p options can come from the environment.
620 * Improved support for USG and HPUX (hopefully).
622 * A variable reference like `$(foo:a=b)', if `a' contains a `%', is
623 equivalent to `$(patsubst a,b,$(foo))'.
625 * Defining .DEFAULT with no deps or commands clears its commands.
627 * New default implicit rules for .S (cpp, then as), and .sh (copy and make
628 executable). All default implicit rules that use cpp (even indirectly), use
633 * Giving the -j option with no arguments gives you infinite jobs.
637 * New option: "-l LOAD" says not to start any new jobs while others are
638 running if the load average is not below LOAD (a floating-point number).
640 * There is support in place for implementations of remote command execution
641 in Make. See the file remote.c.
645 * No more than 10 directories will be kept open at once.
646 (This number can be changed by redefining MAX_OPEN_DIRECTORIES in dir.c.)
650 * Archive files will have their modification times recorded before doing
651 anything that might change their modification times by updating an archive
656 * The `MAKELEVEL' variable is defined for use by makefiles.
660 * The recursion level indications in error messages are much shorter than
661 they were in version 3.14.
665 * Leading spaces before directives are ignored (as documented).
667 * Included makefiles can determine the default goal target.
668 (System V Make does it this way, so we are being compatible).
672 * Variables that are defaults built into Make will not be put in the
673 environment for children. This just saves some environment space and,
674 except under -e, will be transparent to sub-makes.
676 * Error messages from sub-makes will indicate the level of recursion.
678 * Hopefully some speed-up for large directories due to a change in the
679 directory hashing scheme.
681 * One child will always get a standard input that is usable.
683 * Default makefiles that don't exist will be remade and read in.
687 * Count parentheses inside expansion function calls so you can
688 have nested calls: `$(sort $(foreach x,a b,$(x)))'.
692 * Several bug fixes, including USG and Sun386i support.
694 * `shell' function to expand shell commands a la `
696 * If the `-d' flag is given, version information will be printed.
698 * The `-c' option has been renamed to `-C' for compatibility with tar.
700 * The `-p' option no longer inhibits other normal operation.
702 * Makefiles will be updated and re-read if necessary.
704 * Can now run several commands at once (parallelism), -j option.
706 * Error messages will contain the level of Make recursion, if any.
708 * The `MAKEFLAGS' and `MFLAGS' variables will be scanned for options after
711 * A double-colon rule with no dependencies will always have its commands run.
712 (This is how both the BSD and System V versions of Make do it.)
716 (Changes from versions 1 through 3.05 were never recorded. Sorry.)
718 ----------------------------------------------------------------------
719 Copyright information:
721 Permission is granted to anyone to make or distribute verbatim copies
722 of this document as received, in any medium, provided that the
723 copyright notice and this permission notice are preserved, thus
724 giving the recipient permission to redistribute in turn.
726 Permission is granted to distribute modified versions of this
727 document, or of portions of it, under the above conditions, provided
728 also that they carry prominent notices stating who last changed them.