* libc/time/strftime.c (strftime): Change %r and %x to be compliant
to POSIX standard for "C" locale. Allow %E and %O modifiers
to be ignored as long as they precede valid specifiers according
to POSIX.
* libc/include/time.h (tzset, _tzset_r): Added prototypes.
(strptime): Moved prototype to be within !__STRICT_ANSI__.
(_tzname, _daylight, _timezone): No long __CYGWIN__ only.
(tzname): Defined for all platforms.
(daylight, timezone): Defined only for CYGWIN.
* libc/sys/linux/machine/i386/crt0.c: Add call to tzset() after
environment set up.
* libc/stdlib/setenv_r.c (_setenv_r): Call tzset() if the TZ
environment variable is set.
* libc/time/Makefile.am: Add support for tzset.c, tzlock.c, and
tzset_r.c.
* libc/time/Makefile.in: Regenerated.
* libc/time/gmtime.c (gmtime): Changed to call gmtime_r.
* libc/time/gmtime_r.c (gmtime_r): Changed to call _mktm_r.
* libc/time/lcltime_r.c (lcltime_r): Ditto.
* libc/time/local.h: New local header file.
* libc/time/mktime.c (mktime): Add timezone support.
* libc/time/mktm_r.c: New file which is the common engine
for gmtime_r and lcltime_r. This code has timezone support.
* libc/time/strftime.c (strftime): Add %Z timezone support.
* libc/time/tzlock.c: New file containing timezone lock stubs.
* libc/time/tzset.c: New file containing tzset() routine.
* libc/time/tzset_r.c: New file containing _tzset_r and
internal routine for calculating timezone changes for specified year.
* libc/include/sys/reent.h: Add include of <sys/_types.h>.
No longer include time.h. Add struct __tm to use for
_localtime_buf in the reentrant structure. Add a
_NULL definition to use in initializing the reentrant struct.
* libc/include/sys/config.h: For CYGWIN32 and RTEMS, change
the _READ_WRITE_RETURN_TYPE to _ssize_t which is found in
<sys/_types.h>.
* libc/include/sys/unistd.h: Include <sys/_types.h>.
* libc/time/lcltime.c (localtime): Cast the reentrant struct
_localtime_buf to be struct tm *.