re PR middle-end/46790 (EH failures in libstdc++ testsuite with --gc-sections and...

re PR middle-end/46790 (EH failures in libstdc++ testsuite with --gc-sections and GNU ld 2.18)

	PR middle-end/46790
	* configure.ac (HAVE_LD_EH_GC_SECTIONS_BUG): New test.
	* configure: Regenerated.
	* config.in: Regenerated.
	* varasm.c (default_function_section): Return NULL
	if HAVE_LD_EH_GC_SECTIONS_BUG and decl has implicit
	section name.

From-SVN: r170565