Merge from gcc:

Merge from gcc:

	2010-05-18  Steven Bosscher  <steven AT gcc.gnu.org>
	* configure.ac (--enable-lto): All *-apple-darwin* now support LTO.
	* configure: Regenerate.

	2010-05-07  Steven Bosscher  <steven AT gcc.gnu.org>
	* configure.ac (--enable-lto): Add x86_64-apple-darwin* as
	a platform that supports LTO.
	* configure: Regenerate.

	2010-04-27  Dave Korn  <dave.korn.cygwin AT gmail.com>
	PR lto/42776
	* configure.ac (--enable-lto): Refactor handling so libelf tests
	are only performed inside then-clause of ACX_ELF_TARGET_IFELSE,
	and allow LTO to be explicitly enabled on non-ELF platforms that
	are known to support it inside else-clause.
	* configure: Regenerate.