Support slim LTO bootstrap

Support slim LTO bootstrap

Change the bootstrap-lto config file to use slim (non fat) LTO..
Speeds up the LTO bootstrap by ~18% on a 4 core system.

This requires using gcc-ar/ranlib in post stage 1 builds, so these
are passed to all sub builds.

config/:

2014-09-01  Andi Kleen  <ak@linux.intel.com>

	* bootstrap-lto.mk: Implement slim bootstrap.

/:
2014-09-01  Andi Kleen  <ak@linux.intel.com>

	* Makefile.tpl (POSTSTAGE1_HOST_EXPORTS): Add LTO_EXPORTS.
	POSTSTAGE1_FLAGS_TO_PASS):  Add LTO_FLAGS_TO_PASS.
	* Makefile.in: Regenerate.

From-SVN: r214801