<sys/linux-syscalls.h> only contains constants for the syscalls
we're generating stubs for. We want all the syscalls available
on the architecture in question.
Keep using <sys/linux-syscalls.h> on ARM for now because the
__NR_ARM_set_tls and __NR_ARM_cacheflush values aren't in <asm/unistd.h>.
Change-Id: I66683950d87d9b18d6107d0acc0ed238a4496f44
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
