c-family/
	* c-common.h (c_omp_check_context_selector,
	c_omp_get_context_selector): Declare.
	* c-omp.c (c_omp_declare_simd_clauses_to_numbers): Fix spelling
	in diagnostic message.
	(c_omp_check_context_selector, c_omp_get_context_selector): New
	functions.
	* c-attribs.c (c_common_attribute_table): Add "omp declare variant"
	attribute.
	(handle_omp_declare_variant_attribute): New function.
c/
	* c-parser.c (c_parser_omp_all_clauses): Add NESTED_P argument, if
	true, terminate processing on closing paren and don't skip to end of
	pragma line.
	(c_parser_omp_declare_simd): Handle also declare variant.
	(omp_construct_selectors, omp_device_selectors,
	omp_implementation_selectors, omp_user_selectors): New variables.
	(c_parser_omp_context_selector,
	c_parser_omp_context_selector_specification,
	c_finish_omp_declare_variant): New functions.
	(c_finish_omp_declare_simd): Handle both declare simd and
	declare variant.
	(c_parser_omp_declare): Handle declare variant.
cp/
	* parser.h (struct cp_omp_declare_simd_data): Add variant_p member.
	* parser.c (cp_ensure_no_omp_declare_simd): Handle both declare simd
	and declare variant.
	(cp_parser_oacc_all_clauses): Formatting fix.
	(cp_parser_omp_all_clauses): Add NESTED_P argument, if true, terminate
	processing on closing paren and don't skip to end of pragma line.
	(cp_parser_omp_declare_simd): Add VARIANT_P argument.  Handle also
	declare variant.
	(omp_construct_selectors, omp_device_selectors,
	omp_implementation_selectors, omp_user_selectors): New variables.
	(cp_parser_omp_context_selector,
	cp_parser_omp_context_selector_specification,
	cp_finish_omp_declare_variant): New functions.
	(cp_parser_late_parsing_omp_declare_simd): Handle also declare variant.
	(cp_parser_omp_declare): Handle declare variant.
testsuite/
	* c-c++-common/gomp/declare-variant-1.c: New test.
	* c-c++-common/gomp/declare-variant-2.c: New test.
	* c-c++-common/gomp/declare-variant-3.c: New test.
	* g++.dg/gomp/this-1.C: Adjust for diagnostic message spelling fix.
	* gcc.dg/gomp/declare-variant-1.c: New test.
	* gcc.dg/gomp/declare-variant-2.c: New test.

From-SVN: r276789