[PATCH v3] Always define __USE_TIME_BITS64 when 64 bit time_t is used

[DJ Delorie]

Sorry for the delay in this.

This looks like a mostly mechanical patch, but I have a few general
comments...

First, the patch no longer applies cleanly, but only because three
instances of __GLIBC_USE (ISOC2X) have been replaced with __GLIBC_USE
(ISOC23) in the context around your changes in time/time.h.  I don't
consider this a problem with the patch, just making you aware.

Second, this new macro is not documented anywhere.  Given the confusion
about the old macros, I think a comment in manual/maint.texi (@node
64-bit time symbol handling) or sysdeps/generic/features-time64.h would
be useful.  Especially if it's not intended to be used outside of glibc,
yet is visible outside of glibc.  It would be better if it could be made
to be not visible outside of glibc or glibc's headers, but...

Third, there are many cases of an if/else/endif clause where the change
was made to the if but not the else or endif:

./io/fcntl.h:	#else /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/arm/bits/struct_stat.h:	#endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/arm/bits/struct_stat.h:	# endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/hppa/bits/struct_stat.h:	#endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/hppa/bits/struct_stat.h:	# endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/m68k/bits/struct_stat.h:	#endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/m68k/bits/struct_stat.h:	# endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/microblaze/bits/struct_stat.h:	#endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/microblaze/bits/struct_stat.h:	# endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/microblaze/bits/struct_stat.h:	# endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/mips/bits/struct_stat.h:	# endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/mips/bits/struct_stat.h:	# endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/mips/bits/struct_stat.h:	# endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/powerpc/bits/struct_stat.h:	# endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/powerpc/bits/struct_stat.h:	# endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/sh/bits/struct_stat.h:	#endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/sh/bits/struct_stat.h:	# endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/sparc/bits/struct_stat.h:	#endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/sparc/bits/struct_stat.h:	# endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/x86/bits/struct_stat.h:	#endif /* __USE_TIME_BITS64 */ 
./sysdeps/unix/sysv/linux/x86/bits/struct_stat.h:	# endif /* __USE_TIME_BITS64 */