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b045574cb2
Since 1993, Autoconf has been assuming that it is safe to include any
of the headers defined by ISO C90 without checking for them; this is
inaccurate, since only a subset are necessarily available in a
C90 *freestanding* environment.
It is OK to assume the presence of a header in a macro that checks
specifically for something declared by that header (if the header is
not present, we will think the specific declaration is unavailable,
which is probably accurate for modern embedded environments). It is
also OK to continue recommending that user code use these headers
unconditionally—anyone working with a freestanding environment knows
it. But it is not OK for very generic code within Autoconf itself,
such as AC_INCLUDES_DEFAULT, to make this assumption.
Note that the set of headers that are not always available includes
stdio.h, which we have been assuming can be included unconditionally
for even longer.
In AC_INCLUDES_DEFAULT, revert to checking for string.h and stdlib.h
before including them. Also revert to defining STDC_HEADERS only when
string.h and stdlib.h are available (but do not check for float.h and
stdarg.h, as these are part of the freestanding set). Add a new check
for stdio.h. Sort the inclusion list by standard (C90 freestanding;
C90 hosted; C99; POSIX) and alphabetically within each group. Revise
all the documentation and update the testsuite.
This partially reverts commit
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| bin | ||
| build-aux | ||
| doc | ||
| lib | ||
| m4 | ||
| man | ||
| tests | ||
| .gitattributes | ||
| .gitignore | ||
| .prev-version | ||
| .x-update-copyright | ||
| AUTHORS | ||
| BUGS | ||
| cfg.mk | ||
| ChangeLog.0 | ||
| ChangeLog.1 | ||
| ChangeLog.2 | ||
| ChangeLog.3 | ||
| configure.ac | ||
| COPYING | ||
| COPYING.EXCEPTION | ||
| COPYINGv3 | ||
| GNUmakefile | ||
| HACKING | ||
| maint.mk | ||
| Makefile.am | ||
| NEWS | ||
| README | ||
| README-alpha | ||
| README-hacking | ||
| THANKS | ||
| TODO | ||
-*- text -*- Autoconf Autoconf is an extensible package of M4 macros that produce shell scripts to automatically configure software source code packages. These scripts can adapt the packages to many kinds of UNIX-like systems without manual user intervention. Autoconf creates a configuration script for a package from a template file that lists the operating system features that the package can use, in the form of M4 macro calls. Producing configuration scripts using Autoconf requires GNU M4 and Perl. You should install GNU M4 (version 1.4.6 or later is required; 1.4.14 or later is recommended) and Perl (5.006 or later) before configuring Autoconf, so that Autoconf's configure script can find them. The configuration scripts produced by Autoconf are self-contained, so their users do not need to have Autoconf (or GNU M4, Perl, etc.). You can get GNU M4 here: https://ftp.gnu.org/gnu/m4/ The file INSTALL should be distributed with packages that use Autoconf-generated configure scripts and Makefiles that conform to the GNU coding standards. The package's README can just give an overview of the package, where to report bugs, and a pointer to INSTALL for instructions on compilation and installation. This removes the need to maintain many similar sets of installation instructions. Be sure to read BUGS and INSTALL. Mail suggestions to autoconf@gnu.org, report bugs to bug-autoconf@gnu.org, and submit patches to autoconf-patches@gnu.org. All changes can be tracked at the read-only autoconf-commit@gnu.org. Always include the Autoconf version number, which you can get by running `autoconf --version'. Archives of bug-autoconf@gnu.org can be found in <https://lists.gnu.org/archive/html/bug-autoconf/>, and similarly for the other mailing lists. Licensing Autoconf is released under the General Public License version 3 (GPLv3+). Additionally, Autoconf includes a licensing exception in some of its source files; see the respective copyright notices for how your project is impacted by including scripts generated by Autoconf, and the COPYING.EXCEPTION file for the exception in terms of the Additional Permissions as described in section 7 of GPLv3. For more licensing information, see <https://www.gnu.org/licenses/gpl-faq.html> and <https://www.gnu.org/licenses/exceptions.html>. For any copyright year range specified as YYYY-ZZZZ in this package note that the range specifies every single year in that closed interval. ----- Copyright (C) 1992-1994, 1998, 2000-2017, 2020 Free Software Foundation, Inc. Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved. This file is offered as-is, without warranty of any kind.