ARM: Fix clone build for ARMv4

ARMv4 does not have the blx instruction, so use the BLX macro which
handles abstracting this for us.

Build tested for armv7, armv4t and armv4.

ports/ChangeLog.arm:

2014-01-24  Will Newton  <will.newton@linaro.org>

	[BZ #16499]
	* sysdeps/unix/sysv/linux/arm/clone.S: Use BLX macro instead
	of blx instruction directly.

(cherry picked from commit 47590bce28616abbcee93457da91d65a7a07589b)
alpha: Fix tls-macros.h

Reported to the gcc bugzilla, there was a missing dependency on $gp
that let the compiler generated $gp reload be scheduled across the
macros here.

(cherry picked from commit 4ab6acaebd0047dc37c6493946484be9f1b4920b)