Revert "definitions.mk: Don't use GCC '@' parameter"

This reverts commit 85f3b219719657150c5bb63663983ea5a18be662.

Change-Id: Ic216e2e1095b6b31030e6a0895b8aede6ac229c1
Remove useless x86 options that were always hardcoded on.

ARCH_X86_HAVE_MMX, ARCH_X86_HAVE_SSE, ARCH_X86_HAVE_SSE2,
and ARCH_X86_HAVE_SSE3 were all always on. There are no longer any makefiles
or code that are conditional on any of these, so let's just remove them
rather than encourage anyone to mess with knobs that don't work.

Change-Id: I5ee095e8041eecff4554ad4801894fbfca69093f

Conflicts:
	core/combo/TARGET_linux-x86.mk
	core/combo/TARGET_linux-x86_64.mk
	core/combo/arch/x86/haswell.mk
	core/combo/arch/x86/ivybridge.mk
	core/combo/arch/x86/sandybridge.mk
	core/combo/arch/x86/x86-atom.mk
	core/combo/arch/x86_64/x86_64.mk
use isl 0.12.1 by default

Still does not override --with-isl-version

Change-Id: Ie8930afae63219d10f85ebbda5fea074e7e94b58

Conflicts:
	configure
	configure.ac