Adding upstream version 2.52+20231210.upstream/2.52+20231210

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 660 insertions, 0 deletions

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+* Major changes in Autoconf 2.52                       -*- outline -*-
+** Documentation
+- AC_ARG_VAR
+- Quadrigraphs
+  This feature was present in autoconf 2.50 but was not documented.
+  For example, `@<:@' is translated to `[' just before output.  This
+  is useful when writing strings that contain unbalanced quotes, or
+  other hard-to-quote constructs.
+- m4_pattern_forbid, m4_pattern_allow
+- Tips for upgrading from 2.13.
+- Using autoscan to maintain a configure.ac.
+
+** Default includes
+- Now include stdint.h.
+- sys/types.h and sys/stat.h are guarded.
+- strings.h is included if available, and not conflicting with string.h.
+
+** Bug fixes
+- The test suite is more robust and presents less false failures.
+- Invocation of GNU M4 now robust to POSIXLY_CORRECT.
+- configure accepts --prefix='' again.
+- AC_CHECK_LIB works properly when its first argument is not a
+  literal.
+- HAVE_INTTYPES_H is defined only if not conflicting with sys/types.h.
+- build_, host_, and target_alias are AC_SUBST as in 2.13.
+- AC_ARG_VAR properly propagates precious variables inherited from the
+  environment to ./config.status.
+- Using --program-suffix/--program-prefix is portable.
+- Failures to detect the default compiler's output extension are less
+  likely.
+- `config.status foo' works properly when `foo' depends on variables
+  set in an AC_CONFIG_THING INIT-CMD.
+- autoheader is more robust to broken input.
+- Fixed Fortran name-mangling and link tests on a number of systems,
+  e.g. NetBSD; see AC_F77_DUMMY_MAIN, below.
+
+** Generic macros
+- AC_CHECK_HEADER and AC_CHECK_HEADERS support a fourth argument to
+  specify pre-includes.  In this case, the headers are compiled with
+  cc, not merely preprocessed by cpp.  Therefore it is the _usability_
+  of a header which is checked for, not just its availability.
+- AC_ARG_VAR refuses to run configure when precious variables have
+  changed.
+- Versions of compilers are dumped in the logs.
+- AC_CHECK_TYPE recognizes use of `foo_t' as a replacement type.
+
+** Specific Macros
+- AC_PATH_XTRA only adds -ldnet to $LIBS if it's needed to link.
+- AC_FUNC_WAIT3 and AC_SYS_RESTARTABLE_SYSCALLS are obsoleted.
+- AM_FUNC_ERROR_AT_LINE, AM_FUNC_FNMATCH, AM_FUNC_MKTIME,
+  AM_FUNC_OBSTACK, and AM_FUNC_STRTOD are now activated.
+  Be sure to read `Upgrading from Version 2.13' to understand why
+  running `autoupdate' is needed.
+- AC_F77_DUMMY_MAIN, AC_F77_MAIN: new macros to detect whether
+  a main-like routine is required/possible when linking C/C++ with
+  Fortran.  Users of e.g. AC_F77_WRAPPERS should be aware of these.
+- AC_FUNC_GETPGRG behaves better when cross-compiling.
+
+* Major changes in Autoconf 2.50
+
+** Lots of bug fixes
+There have been far too many to enumerate them here.  Check out
+ChangeLog if you really want to know more.
+
+** Improved documentation
+In particular, portability issues are better covered.
+
+** Use of Automake
+All the standard GNU Makefile targets are supported.  The layout has
+changed: m4/ holds the m4 extensions Autoconf needs for its
+configuration, doc/ contains the documentation, and tests/ contains
+the test suite.
+
+** Man pages are provided
+For autoconf, autoreconf, autoupdate, autoheader, autoscan, ifnames,
+config.guess, config.sub.
+
+** autoconf
+- --trace
+  Provides a safe and powerful means to trace the macro uses.  This
+  provide the parsing layer for tools which need to `study'
+  configure.in.
+
+- --warnings
+  Specify what category of warnings should be enabled.
+
+- When recursing into subdirectories, try for configure.gnu before
+  configure to adapt for packages not using autoconf on case-insensitive
+  filesystems.
+
+- Diagnostics
+  More errors are now caught (circular AC_REQUIRE dependencies,
+  AC_DEFINE in the action part of an AC_CACHE_CHECK, too many pops
+  etc.).  In addition, their location and call stack are given.
+
+** autoupdate
+autoupdate is much more powerful, and is able to provide the glue code
+which might be needed to move from an old macro to its newer
+equivalent.
+
+You are strongly encouraged to use it to modernize both your
+`configure.in' and your .m4 extension files.
+
+** autoheader
+The internal machinery of autoheader has completely changed.  As a
+result, using `acconfig.h' should be considered to be obsoleted, and
+you are encouraged to get rid of it using the AH macros.
+
+** autoreconf
+Extensive overhaul.
+
+** Fortran 77 compilers
+Globally, the support for Fortran 77 is considerably improved.
+
+Support for automatically determining a Fortran 77 compiler's
+name-mangling scheme.  New CPP macros F77_FUNC and F77_FUNC_ are
+provided to wrap C/C++ identifiers, thus making it easier and more
+transparent for C/C++ to call Fortran 77 routines, and Fortran 77 to
+call C/C++ routines.  See the Texinfo documentation for details.
+
+** Test suite
+The test suite no longer uses DejaGNU.  It should be easy to submit
+test cases in this new framework.
+
+** configure
+- --help, --help=long, -hl
+  no longer dumps useless items.
+- --help=short, -hs
+  lists only specific options.
+- --help=recursive, -hr
+  displays the help of all the embedded packages.
+- Remembers environment variables when reconfiguring.
+  The previous scheme to set envvar before running configure was
+    ENV=VAL ./configure
+  what prevented configure from remembering the environment in which
+  it was run, therefore --recheck was run in an inconsistent
+  environment.  Now, one should run
+    ./configure ENV=VAR
+  and then --recheck will work properly.  Variables declared with
+  AC_ARG_VAR are also preserved.
+- cross-compilation
+  $build defaults to `config.guess`, $host to $build, and then $target
+  to $host.
+  Cross-compilation is a global status of the package, it no longer
+  depends upon the current language.
+  Cross compilation is enabled iff the user specified `--host'.
+  `configure' now fails if it can't run the executables it compiles,
+  unless cross-compilation is enabled.
+- Cache file
+  The cache file is disabled by default.  The new options
+  `--config-cache', `-C' set the cache to `config.cache'.
+
+** config.status
+- faster
+  Much faster on most architectures.
+- concurrent executions
+  It is safe to use `make -j' with config.status.
+- human interface improved
+  It is possible to invoke
+    ./config.status foobar
+  instead of the former form (still valid)
+    CONFIG_COMMANDS= CONFIG_HEADERS= CONFIG_LINKS= \
+    CONFIG_FILES=foobar:foo.in:bar.in \
+    ./config.status
+  The same holds for configuration headers and links.
+  You can instantiate unknown files and headers:
+    ./config.status --header foo.h:foo.h.in --file bar:baz
+- has a useful --help
+- accepts special file name "-" for stdin/stdout
+
+
+** Identity Macros
+- AC_COPYRIGHT
+  Specify additional copyright information.
+
+- AC_INIT
+  Now expects the identity of the package as argument.
+
+** General changes.
+- Uniform quotation
+  Most macros, if not all, now strictly follow the `one quotation
+  level' rule.  This results in a more predictable expansion.
+
+- AC_REQUIRE
+  A sly bug in the AC_REQUIRE machinery, which could produce incorrect
+  configure scripts, was fixed by Axel Thimm.
+
+** Setup Macros
+- AC_ARG_VAR
+  Document and ask for the registration of an envvar.
+
+- AC_CONFIG_SRCDIR
+  Specifies the file which `configure' should look for when trying to
+  find the source tree (used to be handled by AC_INIT).
+
+- AC_CONFIG_COMMANDS
+  To add new actions to config.status.  Should be used instead of
+  AC_OUTPUT_COMMANDS.
+
+- AC_CONFIG_LINKS
+  Replaces AC_LINK_FILES.
+
+- AC_CONFIG_HEADERS, AC_CONFIG_COMMANDS, AC_CONFIG_SUBDIRS,
+  AC_CONFIG_LINKS, and AC_CONFIG_FILES
+  They now obey sh: you should no longer use shell variables as
+  argument.  Instead of
+
+        test "$package_foo_enabled" = yes && $my_subdirs="$my_subdirs foo"
+        AC_CONFIG_SUBDIRS($my_subdirs)
+
+  write
+
+        if test "$package_foo_enabled" = yes; then
+          AC_CONFIG_SUBDIRS(foo)
+        fi
+
+- AC_HELP_STRING
+  To format an Autoconf macro's help string so that it looks pretty
+  when the user executes `configure --help'.
+
+
+** Generic Test Macros
+- AC_CHECK families
+  The interface of the AC_CHECK families of macros (decl, header,
+  type, member, func) is now uniform.  They support the same set of
+  default includes.
+
+- AC_CHECK_DECL, AC_CHECK_DECLS
+  To check whether a symbol is declared.
+
+- AC_CHECK_SIZEOF, AC_C_CHAR_UNSIGNED.
+  No longer need a cross-compilation default.
+
+- AC_CHECK_TYPE
+  The test it performs is much more robust than previously, and makes
+  it possible to test builtin types in addition to typedefs.
+  It is now schizophrenic:
+    - AC_CHECK_TYPE(TYPE, REPLACEMENT)
+      remains for backward compatibility, but its use is discouraged.
+    - AC_CHECK_TYPE(TYPE, IF-FOUND, IF-NOT-FOUND, INCLUDES)
+      behaves exactly like the other AC_CHECK macros.
+
+- AC_CHECK_TYPES
+  Checks whether given types are supported by the system.
+
+- AC_CHECK_MEMBER, AC_CHECK_MEMBERS
+  Check for given members in aggregates (e.g., pw_gecos in struct
+  passwd).
+
+- AC_PROG_CC_STDC
+  Checks if the compiler supports ISO C, included when needs special
+  options.
+
+- AC_PROG_CPP
+  Checking whether the preprocessor indicates missing includes by the
+  error code. stderr is checked by AC_TRY_CPP only as a fallback.
+
+- AC_LANG
+  Takes a language as argument and replaces AC_LANG_C,
+  AC_LANG_CPLUSPLUS and AC_LANG_FORTRAN77.
+
+- AC_LANG_PUSH, AC_LANG_POP
+  Are preferred to AC_LANG_SAVE, AC_LANG_RESTORE.
+
+** Specific Macros
+- AC_FUNC_CHOWN, AC_FUNC_MALLOC, AC_FUNC_STRERROR_R,
+  AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK, AC_FUNC_STAT, AC_FUNC_LSTAT,
+  AC_FUNC_ERROR_AT_LINE, AC_FUNC_OBSTACK, AC_FUNC_STRTOD, AC_FUNC_FSEEKO.
+  New.
+
+- AC_FUNC_GETGROUPS
+  Sets GETGROUPS_LIBS.
+
+- AC_FUNC_GETLOADAVG
+  Defines `HAVE_STRUCT_NLIST_N_UN_N_NAME' instead of `NLIST_NAME_UNION'.
+
+- AC_PROG_LEX
+  Now integrates `AC_DECL_YYTEXT' which is obsoleted.
+
+- AC_SYS_LARGEFILE
+  Arrange for large-file support.
+
+- AC_EXEEXT, AC_OBJEXT
+  You are no longer expected to use them: their computation is
+  performed by default.
+
+** C++ compatibility
+  Every macro has been revisited in order to support at best CC=c++.
+
+Major changes in Autoconf 2.14:
+  There was no release of GNU Autoconf 2.14.
+
+Major changes in Autoconf 2.13:
+
+* Support for building on Win32 systems where the only available C or
+  C++ compiler is the Microsoft Visual C++ command line compiler
+  (`cl').  Additional support for building on Win32 systems which are
+  using the Cygwin or Mingw32 environments.
+* Support for alternative object file and executable file extensions.
+  On Win32, for example, these are .obj and .exe. These are discovered
+  using AC_OBJEXT and AC_EXEEXT, which substitute @OBJEXT@ and
+  @EXEEXT@ in the output, respectively.
+* New macros: AC_CACHE_LOAD, AC_CACHE_SAVE, AC_FUNC_SELECT_ARGTYPES,
+  AC_VALIDATE_CACHED_SYSTEM_TUPLE, AC_SEARCH_LIBS, AC_TRY_LINK_FUNC,
+  AC_C_STRINGIZE, AC_CHECK_FILE(S), AC_PROG_F77 (and friends).
+* AC_DEFINE now has an optional third argument for a description to be
+  placed in the config header input file (e.g. config.h.in).
+* The C++ code fragment compiled for the C++ compiler test had to be
+  improved to include an explicit return type for main(). This was
+  causing failures on systems using recent versions of the EGCS C++
+  compiler.
+* Fixed an important bug in AC_CHECK_TYPE that would cause a configure
+  script to report that `sometype_t' was present when only `type_t'
+  was defined.
+* Merge of the FSF version of config.guess and config.sub to modernise
+  these scripts. Add support for a few new hosts in config.guess.
+  Incorporate latest versions of install-sh, mkinstalldirs and
+  texinfo.tex from the FSF.
+* autoreconf is capable of running automake if necessary (and
+  applicable).
+* Support for Fortran 77. See the Texinfo documentation for details.
+* Bug fixes and workarounds for quirky bugs in vendor utilities.
+
+Major changes in Autoconf 2.12:
+
+* AC_OUTPUT and AC_CONFIG_HEADER can create output files by
+  concatenating multiple input files separated by colons, like so:
+  AC_CONFIG_HEADER(config.h:conf.pre:config.h.in:conf.post)
+  AC_OUTPUT(Makefile:Makefile.in:Makefile.rules)
+  The arguments may be shell variables, to compute the lists on the fly.
+* AC_LINK_FILES and AC_CONFIG_SUBDIRS may be called multiple times.
+* New macro AC_OUTPUT_COMMANDS adds more commands to run in config.status.
+* Bug fixes.
+
+Major changes in Autoconf 2.11:
+
+* AC_PROG_CC and AC_PROG_CXX check whether the compiler works.
+  They also default CFLAGS/CXXFLAGS to "-g -O2" for gcc, instead of "-g -O".
+* AC_REPLACE_FUNCS defines HAVE_foo if the system has the function `foo'.
+* AC_CONFIG_HEADER expands shell variables in its argument.
+* New macros: AC_FUNC_FNMATCH, AC_FUNC_SETPGRP.
+* The "checking..." messages and the source code for test programs that
+  fail are saved in config.log.
+* Another workaround has been added for seds with small command length limits.
+* config.sub and config.guess recognize more system types.
+* Bug fixes.
+
+Major changes in Autoconf 2.10:
+
+* Bug fixes.
+* The cache variable names used by `AC_CHECK_LIB(LIB, FUNC, ...)' has
+  changed: now $ac_cv_lib_LIB_FUNC, previously $ac_cv_lib_LIB.
+
+Major changes in Autoconfs 2.6 through 2.9:
+
+* Bug fixes.
+
+Major changes in Autoconf 2.5:
+
+* New configure options --bindir, --libdir, --datadir, etc., with
+  corresponding output variables.
+* New macro: AC_CACHE_CHECK, to make using the cache easier.
+* config.log contains the command being run as well as any output from it.
+* AC_CHECK_LIB can check for libraries with "." or "/" or "+" in their name.
+* AC_PROG_INSTALL doesn't cache a path to install-sh, for sharing caches.
+* AC_CHECK_PROG, AC_PATH_PROG, AC_CHECK_PROGS, AC_PATH_PROGS, and
+  AC_CHECK_TOOL can search a path other than $PATH.
+* AC_CHECK_SIZEOF takes an optional size to use when cross-compiling.
+
+Major changes in Autoconf 2.4:
+
+* Fix a few bugs found by Emacs testers.
+
+Major changes in Autoconf 2.3:
+
+* Fix the cleanup trap in several ways.
+* Handle C compilers that are picky about option placement.
+* ifnames gets the version number from the right directory.
+
+Major changes in Autoconf 2.2:
+
+* The ifnames utility is much faster but requires a "new awk" interpreter.
+* AC_CHECK_LIB and AC_HAVE_LIBRARY check and add the new
+  library before existing libs, not after, in case it uses them.
+* New macros: AC_FUNC_GETPGRP, AC_CHECK_TOOL.
+* Lots of bug fixes.
+* Many additions to the TODO file :-)
+
+Major changes in Autoconf 2.1:
+
+* Fix C++ problems.
+* More explanations in the manual.
+* Fix a spurious failure in the testsuite.
+* Clarify some warning messages.
+* autoreconf by default only rebuilds configure and config.h.in files
+  that are older than any of their particular input files; there is a
+  --force option to use after installing a new version of Autoconf.
+
+Thanks to everybody who's submitted changes and additions to Autoconf!
+I've incorporated many of them, and am still considering others for
+future releases -- but I didn't want to postpone this release indefinitely.
+
+Caution: don't indiscriminately rebuild configure scripts with
+Autoconf version 2.  Some configure.in files need minor adjustments to
+work with it; the documentation has a chapter on upgrading.  A few
+configure.in files, including those for GNU Emacs and the GNU C
+Library, need major changes because they relied on undocumented
+internals of version 1.  Future releases of those packages will have
+updated configure.in files.
+
+It's best to use GNU m4 1.3 (or later) with Autoconf version 2.
+Autoconf now makes heavy use of m4 diversions, which were implemented
+inefficiently in GNU m4 releases before 1.3.
+
+Major changes in Autoconf 2.0:
+
+** New copyright terms:
+* There are no restrictions on distribution or use of configure scripts.
+
+** Documentation:
+* Autoconf manual is reorganized to make information easier to find
+  and has several new indexes.
+* INSTALL is reorganized and clearer and is now made from Texinfo source.
+
+** New utilities:
+* autoscan to generate a preliminary configure.in for a package by
+  scanning its source code for commonly used nonportable functions,
+  programs, and header files.
+* ifnames to list the symbols used in #if and #ifdef directives in a
+  source tree.
+* autoupdate to update a configure.in to use the version 2 macro names.
+* autoreconf to recursively remake configure and configuration header
+  files in a source tree.
+
+** Changed utilities:
+* autoheader can take pieces of acconfig.h to replace config.h.{top,bot}.
+* autoconf and autoheader can look for package-local definition files
+  in an alternate directory.
+
+** New macros:
+* AC_CACHE_VAL to share results of tests between configure runs.
+* AC_DEFUN to define macros, automatically AC_PROVIDE them, and ensure
+  that macros invoked with AC_REQUIRE don't interrupt other macros.
+* AC_CONFIG_AUX_DIR, AC_CANONICAL_SYSTEM, AC_CANONICAL_HOST, AC_LINK_FILES to
+  support deciding unguessable features based on the host and target types.
+* AC_CONFIG_SUBDIRS to recursively configure a source tree.
+* AC_ARG_PROGRAM to use the options --program-prefix,
+  --program-suffix, and --program-transform-name to change the names
+  of programs being installed.
+* AC_PREFIX_DEFAULT to change the default installation prefix.
+* AC_TRY_COMPILE to compile a test program without linking it.
+* AC_CHECK_TYPE to check whether sys/types.h or stdlib.h defines a given type.
+* AC_CHECK_LIB to check for a particular function and library.
+* AC_MSG_CHECKING and AC_MSG_RESULT to print test results, on a single line,
+  whether or not the test succeeds.  They obsolete AC_CHECKING and AC_VERBOSE.
+* AC_SUBST_FILE to insert one file into another.
+* AC_FUNC_MEMCMP to check whether memcmp is 8-bit clean.
+* AC_FUNC_STRFTIME to find strftime even if it's in -lintl.
+* AC_FUNC_GETMNTENT to find getmntent even if it's in -lsun or -lseq.
+* AC_HEADER_SYS_WAIT to check whether sys/wait.h is POSIX.1 compatible.
+
+** Changed macros:
+* Many macros renamed systematically, but old names are accepted for
+  backward compatibility.
+* AC_OUTPUT adds the "automatically generated" comment to
+  non-Makefiles where it finds @configure_input@ in an input file, to
+  support files with various comment syntaxes.
+* AC_OUTPUT does not replace "prefix" and "exec_prefix" in generated
+  files when they are not enclosed in @ signs.
+* AC_OUTPUT allows the optional environment variable CONFIG_STATUS to
+  override the file name "config.status".
+* AC_OUTPUT takes an optional argument for passing variables from
+  configure to config.status.
+* AC_OUTPUT and AC_CONFIG_HEADER allow you to override the input-file names.
+* AC_OUTPUT automatically substitutes the values of CFLAGS, CXXFLAGS,
+  CPPFLAGS, and LDFLAGS from the environment.
+* AC_PROG_CC and AC_PROG_CXX now set CFLAGS and CXXFLAGS, respectively.
+* AC_PROG_INSTALL looks for install-sh or install.sh in the directory
+  specified by AC_CONFIG_AUXDIR, or srcdir or srcdir/.. or
+  srcdir/../.. by default.
+* AC_DEFINE, AC_DEFINE_UNQUOTED, and AC_SUBST are more robust and smaller.
+* AC_DEFINE no longer prints anything, because of the new result reporting
+  mechanism (AC_MSG_CHECKING and AC_MSG_RESULT).
+* AC_VERBOSE pays attention to --quiet/--silent, not --verbose.
+* AC_ARG_ENABLE and AC_ARG_WITH support whitespace in the arguments to
+  --enable- and --with- options.
+* AC_CHECK_FUNCS and AC_CHECK_HEADERS take optional shell commands to
+  execute on success or failure.
+* Checking for C functions in C++ works.
+
+** Removed macros:
+* AC_REMOTE_TAPE and AC_RSH removed; too specific to tar and cpio, and
+  better maintained with them.
+* AC_ARG_ARRAY removed because no one was likely using it.
+* AC_HAVE_POUNDBANG replaced with AC_SYS_INTERPRETER, which doesn't
+  take arguments, for consistency with all of the other specific checks.
+
+** New files:
+* Comes with config.sub and config.guess, and uses them optionally.
+* Uses config.cache to cache test results.  An alternate cache file
+  can be selected with the --cache-file=FILE option.
+* Uses optional shell scripts $prefix/share/config.site and
+  $prefix/etc/config.site to perform site or system specific initializations.
+* configure saves compiler output to ./config.log for debugging.
+* New files autoconf.m4 and autoheader.m4 load the other Autoconf macros.
+* acsite.m4 is the new name for the system-wide aclocal.m4.
+* Has a DejaGnu test suite.
+
+Major changes in Autoconf 1.11:
+
+* AC_PROG_INSTALL calls install.sh with the -c option.
+* AC_SET_MAKE cleans up after itself.
+* AC_OUTPUT sets prefix and exec_prefix if they weren't set already.
+* AC_OUTPUT prevents shells from looking in PATH for config.status.
+
+Plus a few other bug fixes.
+
+Major changes in Autoconf 1.10:
+
+* autoheader uses config.h.bot if present, analogous to config.h.top.
+* AC_PROG_INSTALL looks for install.sh in srcdir or srcdir/.. and
+  never uses cp.
+* AC_PROG_CXX looks for cxx as a C++ compiler.
+
+Plus several bugs fixed.
+
+Major changes in Autoconf 1.9:
+
+* AC_YYTEXT_POINTER replaces AC_DECLARE_YYTEXT.
+* AC_SIZEOF_TYPE generates the cpp symbol name automatically,
+  and autoheader generates entries for those names automatically.
+* AC_FIND_X gets the result from xmkmf correctly.
+* AC_FIND_X assumes no X if --without-x was given.
+* AC_FIND_XTRA adds libraries to the variable X_EXTRA_LIBS.
+* AC_PROG_INSTALL finds OSF/1 installbsd.
+
+Major changes in Autoconf 1.8:
+
+** New macros:
+* New macros AC_LANG_C, AC_LANG_CPLUSPLUS, AC_LANG_SAVE, AC_LANG_RESTORE,
+  AC_PROG_CXX, AC_PROG_CXXCPP, AC_REQUIRE_CPP
+  for checking both C++ and C features in one configure script.
+* New macros AC_CHECKING, AC_VERBOSE, AC_WARN, AC_ERROR for printing messages.
+* New macros AC_FIND_XTRA, AC_MMAP, AC_SIZEOF_TYPE, AC_PREREQ,
+  AC_SET_MAKE, AC_ENABLE.
+
+** Changed macros:
+* AC_FIND_X looks for X in more places.
+* AC_PROG_INSTALL defaults to install.sh instead of cp, if it's in srcdir.
+  install.sh is distributed with Autoconf.
+* AC_DECLARE_YYTEXT has been removed because it can't work, pending
+  a rewrite of quoting in AC_DEFINE.
+* AC_OUTPUT adds its comments in C format when substituting in C files.
+* AC_COMPILE_CHECK protects its ECHO-TEXT argument with double quotes.
+
+** New or changed command line options:
+* configure accepts --enable-FEATURE[=ARG] and --disable-FEATURE options.
+* configure accepts --without-PACKAGE, which sets withval=no.
+* configure accepts --x-includes=DIR and --x-libraries=DIR.
+* Giving --with-PACKAGE no argument sets withval=yes instead of withval=1.
+* configure accepts --help, --version, --silent/--quiet, --no-create options.
+* configure accepts and ignores most other Cygnus configure options, and
+  warns about unknown options.
+* config.status accepts --help, --version options.
+
+** Paths and other changes:
+* Relative srcdir values are not made absolute.
+* The values of @prefix@ and @exec_prefix@ and @top_srcdir@ get substituted.
+* Autoconf library files are installed in ${datadir}/autoconf, not ${datadir}.
+* autoheader optionally copies config.h.top to the beginning of config.h.in.
+* The example Makefile dependencies for configure et al. work better.
+* Namespace cleanup: all shell variables used internally by Autoconf
+  have names beginning with `ac_'.
+
+More big improvements are in process for future releases, but have not
+yet been (variously) finished, integrated, tested, or documented enough
+to release yet.
+
+Major changes in Autoconf 1.7:
+
+* New macro AC_OBSOLETE.
+* Bugs in Makefile.in fixed.
+* AC_LONG_FILE_NAMES improved.
+
+Major changes in Autoconf 1.6:
+
+* New macro AC_LONG_64_BITS.
+* Multiple .h files can be created.
+* AC_FIND_X looks for X files directly if it doesn't find xmkmf.
+* AC_ALLOCA defines C_ALLOCA if using alloca.c.
+* --with-NAME can take a value, e.g., --with-targets=sun4,hp300bsd.
+* Unused --no-create option to configure removed.
+* autoheader doesn't change the timestamp of its output file if
+  the file didn't change.
+* All macros that look for libraries now use AC_HAVE_LIBRARY.
+* config.status checks three optional environment variables to
+  modify its behavior.
+* The usual bug fixes.
+
+Major changes in Autoconf 1.5:
+
+* New macros AC_FIND_X, AC_OFF_T, AC_STAT_MACROS_BROKEN, AC_REVISION.
+* autoconf and autoheader scripts have GNU standards conforming
+  --version and --help options (they print their message and exit).
+* Many bug fixes.
+
+Major changes in Autoconf 1.4:
+
+* New macros AC_HAVE_POUNDBANG, AC_TIME_WITH_SYS_TIME, AC_LONG_DOUBLE,
+  AC_GETGROUPS_T, AC_DEFINE_UNQUOTED.
+* autoconf and autoheader use the M4 environment variable to determine the
+  path of the m4 program to use.
+* The --macrodir option to autoconf and autoheader specifies the directory
+  in which acspecific.m4, acgeneral.m4, etc. reside if not the default.
+* autoconf and autoheader can take `-' as their file names, which means to
+  read stdin as input.
+* Resulting configure scripts can take a --verbose option which causes them
+  to print the results of their tests.
+* AC_DEFINE quotes its second argument in such a way that spaces, magic
+  shell characters, etc. will be preserved during various stages of
+  expansion done by the shell.  If you don't want this, use
+  AC_DEFINE_UNQUOTED instead.
+* Much textual processing done with external calls to tr and sed have been
+  internalized with builtin m4 `patsubst' and `translit' calls.
+* AC_OUTPUT doesn't hardwire the filenames it outputs.  Instead, you can
+  set the shell variables `gen_files' and `gen_config' to the list of
+  filenames to output.
+* AC_DECLARE_YYTEXT does an AC_SUBST of `LEX_OUTPUT_ROOT', which may be
+  "lex.yy" or "lexyy", depending on the system.
+* AC_PROGRAMS_CHECK takes an optional third arg.  If given, it is used as
+  the default value.
+* If AC_ALLOCA chooses alloca.c, it also defines STACK_DIRECTION.
+* AC_CONST works much more reliably on more systems.
+* Many bug fixes.
+
+Major changes in Autoconf 1.3:
+
+configure no longer requires awk for packages that use a config.h.
+Support handling --with-PACKAGE options.
+New `autoheader' script to create `config.h.in' from `configure.in'.
+Ignore troublesome -lucb and -lPW when searching for alloca.
+Rename --exec_prefix to --exec-prefix for GNU standards conformance.
+Improve detection of STDC library.
+Add AC_HAVE_LIBRARY to check for non-default libraries.
+Function checking should work with future GNU libc releases.
+
+Major changes in Autoconf 1.2:
+
+The --srcdir option is now usually unnecessary.
+Add a file containing sample comments describing CPP macros.
+A comment in config.status tells which host it was configured on.
+Substituted variable values can now contain commas.
+Fix bugs in various feature checks.
+
+Major changes in Autoconf 1.1:
+
+Added AC_STRCOLL macro.
+Made AC_GETLOADAVG check for more things.
+AC_OUTPUT argument is now optional.
+Various bug fixes.