Peter Eisentraut f5e0186f86 Raise C requirement to C11 ... This changes configure and meson.build to require at least C11, instead of the previous C99. The installation documentation is updated accordingly. configure.ac previously used AC_PROG_CC_C99 to activate C99. But there is no AC_PROG_CC_C11 in Autoconf 2.69, because it's too old. (Also, post-2.69, the AC_PROG_CC_Cnn macros were deprecated and AC_PROG_CC activates the last supported C mode.) We could update the required Autoconf version, but that might be a separate project that no one wants to undertake at the moment. Instead, we open-code the test for C11 using some inspiration from later Autoconf versions. But instead of writing an elaborate test program, we keep it simple and just check __STDC_VERSION__, which should be good enough in practice. In meson.build, we update the existing C99 test to C11, but again we just check for __STDC_VERSION__. This also removes the separate option for the conforming preprocessor on MSVC, added by commit 8fd9bb1d96, since that is activated automatically in C11 mode. Note, we don't use the "official" way to set the C standard in Meson using the c_std project option, because that is impossible to use correctly (see <https://github.com/mesonbuild/meson/issues/14717>). Reviewed-by: David Rowley <dgrowleyml@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/01a69441-af54-4822-891b-ca28e05b215a@eisentraut.org		2025-08-26 11:50:46 +02:00
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src	Raise C requirement to C11	2025-08-26 11:50:46 +02:00
KNOWN_BUGS	Remove extra newlines at end and beginning of files, add missing newlines	2010-08-19 05:57:36 +00:00
Makefile	Remove distprep	2023-11-06 15:18:04 +01:00
MISSING_FEATURES	Remove extra newlines at end and beginning of files, add missing newlines	2010-08-19 05:57:36 +00:00
TODO	Change documentation references to PG website to use https: not http:	2017-05-20 21:50:47 -04:00