Zack Weinberg c03073774f Make _REENTRANT and _THREAD_SAFE aliases for _POSIX_C_SOURCE=199506L. ... For many years, the only effect of these macros has been to make unistd.h declare getlogin_r. _POSIX_C_SOURCE >= 199506L also causes this function to be declared. However, people who don't carefully read all the headers might be confused into thinking they need to define _REENTRANT for any threaded code (as was indeed the case a long time ago). Therefore, remove __USE_REENTRANT, and make _REENTRANT and _THREAD_SAFE into synonyms for _POSIX_C_SOURCE=199506L. This will only affect programs that don't select a higher conformance level some other way. For instance, -std=c89 -D_REENTRANT will see a change in visible declarations, but -std=c99 -D_POSIX_C_SOURCE=200809L -D_REENTRANT won't, and -D_REENTRANT all by itself also won't, because _DEFAULT_SOURCE implies _POSIX_C_SOURCE > 199506. * include/features.h: Remove __USE_REENTRANT. Treat _REENTRANT and _THREAD_SAFE the same as _POSIX_C_SOURCE=199506L, if a higher POSIX conformance level has not been selected by other macros. * NEWS, manual/creature.texi: Document this change. * posix/unistd.h, posix/bits/unistd.h: Don't check __USE_REENTRANT. * include/libc-symbols.h: Don't define _REENTRANT. * scripts/check-installed-headers.sh: Don't undefine _REENTRANT.		2016-12-08 15:45:33 -05:00
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posix1_lim.h	Update copyright dates with scripts/update-copyrights.	2016-01-04 16:05:18 +00:00
posix2_lim.h	Update copyright dates with scripts/update-copyrights.	2016-01-04 16:05:18 +00:00
unistd.h	Make _REENTRANT and _THREAD_SAFE aliases for _POSIX_C_SOURCE=199506L.	2016-12-08 15:45:33 -05:00