* 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 *.
* libc/include/sys/reent.h (_rand_next): Added __extension__
qualifier as long long type is not strict ANSI.
* libc/stdlib/rand.c (rand): Added __extension__ qualifier
to long long constant.
* libc/include/sys/reent.h (_rand_next): Changed to
unsigned long long and moved to end of _reent struct in _new union.
(_REENT_INIT): Changed to move _rand_next initialization.
* libc/stdlib/rand.c (rand): Changed to use unsigned long long
linear congruential algorithm that is used by DJGPP.