C: add fixit hint to misspelled field names

C: add fixit hint to misspelled field names

gcc/c/ChangeLog:
	* c-parser.c (c_parser_postfix_expression): In __builtin_offsetof
	and structure element reference, capture the location of the
	element name token and pass it to build_component_ref.
	(c_parser_postfix_expression_after_primary): Likewise for
	structure element dereference.
	(c_parser_omp_variable_list): Likewise for
	OMP_CLAUSE_{_CACHE, MAP, FROM, TO},
	* c-tree.h (build_component_ref): Add location_t param.
	* c-typeck.c (build_component_ref): Add location_t param
	COMPONENT_LOC.  Use it, if available, when issuing hints about
	mispelled member names to provide a fixit replacement hint.

gcc/objc/ChangeLog:
	* objc-act.c (objc_build_component_ref): Update call
	to build_component_ref for added param, passing UNKNOWN_LOCATION.

gcc/testsuite/ChangeLog:
	* gcc.dg/spellcheck-fields-2.c: New test case.

From-SVN: r237176