* doc/invoke.texi: Document -Wc99-c11-compat.
c-family/
	* c.opt (Wc99-c11-compat): New option.
c/
	* c-decl.c (diagnose_mismatched_decls): Unconditionally call
	pedwarn_c99 instead of pedwarn.
	(grokfield): Likewise.
	(warn_defaults_to): New function.
	(grokdeclarator): Call warn_defaults_to instead of pedwarn_c99.
	Unconditionally call pedwarn_c99 instead of pedwarn.
	(start_function): Call warn_defaults_to instead of pedwarn_c99.
	(declspecs_add_scspec): Call pedwarn_c99 instead of pedwarn, don't
	check flag_isoc11 before.
	* c-errors.c (pedwarn_c99): Change the return type to bool.
	Handle -Wc99-c11-compat.
	* c-parser.c (disable_extension_diagnostics): Handle
	warn_c99_c11_compat.
	(restore_extension_diagnostics): Likewise.
	(c_parser_static_assert_declaration_no_semi): Call pedwarn_c99
	instead of pedwarn, don't check flag_isoc11 before.
	(c_parser_declspecs): Likewise.
	(c_parser_alignas_specifier): Likewise.
	(c_parser_alignof_expression): Likewise.
	(c_parser_generic_selection): Likewise.
	* c-tree.h (pedwarn_c99): Update declaration.
	* c-typeck.c (c_finish_return): Call pedwarn or warning_at instead
	of pedwarn_c99.
testsuite/
	* gcc.dg/Wc99-c11-compat-1.c: New test.
	* gcc.dg/Wc99-c11-compat-2.c: New test.
	* gcc.dg/Wc99-c11-compat-3.c: New test.
	* gcc.dg/Wc99-c11-compat-4.c: New test.
	* gcc.dg/Wc99-c11-compat-5.c: New test.
	* gcc.dg/Wc99-c11-compat-6.c: New test.
	* gcc.dg/Wc99-c11-compat-7.c: New test.

From-SVN: r214133