Also update the x86 asm.h to support this; we need it for libm assembler
anyway.
Also clean up the _FBSDID hack in <sys/cdefs.h>.
Change-Id: Iababd977b8110ec022bf7c93f4d62ece47630e7c
Use tgkill instead of tkill to implement pthread_kill.
This is safer in the event that the thread has already terminated
and its id has been reused by a different process.
Change-Id: Ied715e11d7eadeceead79f33db5e2b5722954ac9