no-executables.m4 (GCC_TRY_COMPILE_OR_LINK): New function.

no-executables.m4 (GCC_TRY_COMPILE_OR_LINK): New function.

config/
	* no-executables.m4 (GCC_TRY_COMPILE_OR_LINK): New function.
	libstdc++-v3/

libstdc++/
	* acinclude.m4 (GLIBCXX_ENABLE_C99): Temporarily add
	-fno-exceptions to CXXFLAGS.  Use GCC_TRY_COMPILE_OR_LINK.
	Make the tests assign results to volatile variables.  Use -lm
	for link tests in GCC_TRY_COMPILE_OR_LINK.  Fall back to
	compile-only tests if -lm is not available.
	* configure: Regenerate.

From-SVN: r128982