Make fopenacc an LTO option

2015-01-23  Tom de Vries  <tom@codesourcery.com>

	PR libgomp/64672
	* lto-opts.c (lto_write_options): Output non-explicit conservative
	-fno-openacc.
	* lto-wrapper.c (merge_and_complain): Handle merging -fopenacc.
	(append_compiler_options): Pass -fopenacc through.

	* c.opt (fopenacc): Mark as LTO option.

	* lang.opt (fopenacc): Mark as LTO option.

	* testsuite/libgomp.oacc-c-c++-common/abort-5.c: New test.

From-SVN: r220038