Only support ifunc in nptl/pt-vfork.c

	* nptl/pt-vfork.c: Error if !HAVE_IFUNC.
	[!HAVE_IFUNC] (vfork_compat): Remove.
	[!HAVE_IFUNC] (DEFINE_VFORK): Remove.
Only provide non-default symbols in libpthread for vfork

	* nptl/pt-vfork.c (vfork_resolve): Rename from vfork_ifunc.
	(vfork, __vfork): Define via compat_symbol.
alpha: Do non-default symbols in pt-vfork.S
aarch64: Fix DO_CALL block comment
aarch64: Remove DOARGS/UNDOARGS macros

While they do something for AArch32, they're useless for AArch64.
aarch64: Tidy syscall error check

Move the error branch from the PSEUDO_RET macro to the PSEUDO macro.
This is in line with other architectures, and will enable further improvments.
arm,aarch64: Remove SINGLE_THREAD_P_PIC

This macro was removed by

2005-11-16  Daniel Jacobowitz  <dan@codesourcery.com>

but not applied to the (still separate) eabi port so necro'd
when the eabi port superceded the old abi.  It was thence
copied into the new AArch64 port.
aarch64: Tabify sysdep-cancel.h
aarch64: Share code in syscall-cancel.h

Fold nocancel and error handling paths.
aarch64: Pass regno parameter to SINGLE_THREAD_P

Use cbz instead of cmp+b.eq.
aarch64: Improve syscall-cancel stack frame

One push instead of N; use stp/ldp to halve the insns.
aarch64: Use tpidr_el0 rather than __read_tp in librt
aarch64: Use tpidr_el0 rather than __errno_location in librt
aarch64: Rely on syscalls preserving registers

In several cases we've had asm routines rely on syscalls not clobbering
call-clobbered registers, and that's now deemed ABI.  So take advantage
of this in the INLINE_SYSCALL path as well.

Shrinks libc.so by about 1k.
aarch64: Consolidate NPTL/non versions of clone

At the same time, rely on non-clobbered registers across syscall
so that we eliminate the stack frame that we previously ignored
in the unwind info.
aarch64: Consolidate NPTL/non versions of vfork

At the same time, incorporate the 0 -> 0x80000000 mapping
of the pid expected by raise.c.