Refer to C23 in place of C2X in glibc

WG14 decided to use the name C23 as the informal name of the next
revision of the C standard (notwithstanding the publication date in
2024).  Update references to C2X in glibc to use the C23 name.

This is intended to update everything *except* where it involves
renaming files (the changes involving renaming tests are intended to
be done separately).  In the case of the _ISOC2X_SOURCE feature test
macro - the only user-visible interface involved - support for that
macro is kept for backwards compatibility, while adding
_ISOC23_SOURCE.

Tested for x86_64.

1 files changed, 5 insertions, 5 deletions

diff --git a/manual/creature.texi b/manual/creature.texi
index fa5dd9d6ad..3fc53619ea 100644
--- a/manual/creature.texi
+++ b/manual/creature.texi
@@ -220,11 +220,11 @@ when the compiler uses an earlier language version.
 If this macro is defined, ISO C11 extensions to ISO C99 are included.
 @end defvr
 
-@defvr Macro _ISOC2X_SOURCE
-@standards{C2X, (none)}
-If this macro is defined, ISO C2X extensions to ISO C11 are included.
+@defvr Macro _ISOC23_SOURCE
+@standards{C23, (none)}
+If this macro is defined, ISO C23 extensions to ISO C11 are included.
 Only some features from this draft standard are supported by
-@theglibc{}.
+@theglibc{}.  The older name @code{_ISOC2X_SOURCE} is also supported.
 @end defvr
 
 @defvr Macro __STDC_WANT_LIB_EXT2__
@@ -260,7 +260,7 @@ enabled.  Only some of the features from this TS are supported by
 
 @defvr Macro __STDC_WANT_IEC_60559_EXT__
 @standards{ISO, (none)}
-If you define this macro, ISO C2X features defined in Annex F of that
+If you define this macro, ISO C23 features defined in Annex F of that
 standard are enabled.  This affects declarations of the
 @code{totalorder} functions and functions related to NaN payloads.
 @end defvr