gcc/
	* doc/sourcebuild.texi (dg-add-c99-runtime-options): Document.

gcc/testsuite/
	* lib/target-supports.exp (add_options_for_c99_runtime): New procedure.
	* lib/target-supports-dg.exp (dg-add-options): Likewise.
	* gcc.dg/builtins-18.c: Use { dg-add-options c99_runtime } instead of
	target-specific dg-options.
	* gcc.dg/builtins-20.c: Likewise.
	* gcc.dg/builtins-53.c: Likewise.
	* gcc.dg/builtins-55.c: Likewise.
	* gcc.dg/single-precision-constant.c: Likewise.
	* gcc.dg/torture/builtin-convert-1.c: Likewise.
	* gcc.dg/torture/builtin-convert-2.c: Likewise.
	* gcc.dg/torture/builtin-convert-3.c: Likewise.
	* gcc.dg/torture/builtin-convert-4.c: Likewise.
	* gcc.dg/torture/builtin-power-1.c: Likewise.

From-SVN: r128663