* Makefile.am: Move cmath stuff into libc/sys/linux.
* Makefile.in: Regenerated.
* configure.host: Default -DMB_CAPABLE for x86-linux.
* libc/include/reent.h: Define _sbrk to take signed int argument.
* libc/include/sys/unistd.h: Ditto for _sbrk_r and sbrk.
* libc/locale/locale.c[MB_CAPABLE]: Add LC_MESSAGES support and
make locale name checking more efficient. Also allow "C-ISO-8859-1"
locale for LC_CTYPE and LC_MESSAGES.
* libc/reent/sbrkr.c: Change prototype to take ptrdiff_t.
* libc/sys/linux/brk.c: Change sbrk prototype.
* libc/sys/linux/include/time.h: Remove Cygwin stuff and
include <sys/features.h>.
(CLOCK_THREAD_CPUTIME): Renamed to CLOCK_THREAD_CPUTIME_ID.
(CLOCK_PROCESS_CPUTIME): Renamed to CLOCK_PROCESS_CPUTIME_ID.
* libc/sys/linux/sys/cdefs.h: Replace with glibc sys/cdefs.h
with a few local additions.
* libc/sys/linux/sys/features.h: New file.
* libc/sys/linux/sys/unistd.h: Change _sbrk_r and sbrk prototypes
to take signed argument.
* libc/syscalls/syssbrk.c: Change sbrk, _sbrk_r, and _sbrk
prototypes to take signed size argument.