C FE: implement fix-it hint for -Wmissing-braces

C FE: implement fix-it hint for -Wmissing-braces

gcc/c/ChangeLog:
	* c-parser.c (c_parser_declaration_or_fndef): Create a
	rich_location at init_loc and parse it to start_init.
	(last_init_list_comma): New global.
	(c_parser_braced_init): Update last_init_list_comma when parsing
	commas.  Pass it to pop_init_level.  Pass location of closing
	brace to pop_init_level.
	(c_parser_postfix_expression_after_paren_type): Create a
	rich_location at type_loc and parse it to start_init.
	(c_parser_omp_declare_reduction): Likewise for loc.
	* c-tree.h (start_init): Add rich_location * param.
	(pop_init_level): Add location_t param.
	* c-typeck.c (struct initializer_stack): Add field
	"missing_brace_richloc".
	(start_init): Add richloc param, use it to initialize
	the stack node's missing_brace_richloc.
	(last_init_list_comma): New decl.
	(finish_implicit_inits): Pass last_init_list_comma to
	pop_init_level.
	(push_init_level): When finding missing open braces, add fix-it
	hints to the richloc.
	(pop_init_level): Add "insert_before" param and pass it
	when calling pop_init_level.  Add fixits about missing
	close braces to any richloc.  Use the richloc for the
	-Wmissing-braces warning.
	(set_designator): Pass last_init_list_comma to pop_init_level.
	(process_init_element): Likewise.

gcc/testsuite/ChangeLog:
	* gcc.dg/Wmissing-braces-fixits.c: New test case.

From-SVN: r244061