Define.
* sysdeps/mips/sys/asm.h: Test _MIPS_ISA against them on all
ISA tests.
(ALSZ, ALMASK, SZREG, REG_S, REG_L): Define based on ABI, not ISA.
(PTR_ADD, etc): Test _MIPS_SZPTR instead of _MIPS_SZLONG.
* sysdeps/unix/sysv/linux/mips/bits/sigaction.h: Use _MIPS_SZPTR
to decide whether to add padding.
* sysdeps/unix/sysv/linux/mips/bits/sigaction.h: Use _MIPS_SZPTR
to decide whether to add padding.
* sysdeps/unix/sysv/linux/mips/kernel_sigaction.h (struct
old_kernel_sigaction): Likewise.