* builtin-attrs.def (__builtin_printf_unlocked,
	__builtin_fprintf_unlocked, printf_unlocked, fprintf_unlocked):
	Mark with the __printf__ attribute.

	* builtins.c (expand_builtin_fputs): Add an `unlocked' parameter
	and set the replacement function depending on it.
	(expand_builtin): Skip BUILT_IN_*_UNLOCKED when not optimizing.
	Handle BUILT_IN_*_UNLOCKED when optimizing.

	* builtins.def (DEF_EXT_FALLBACK_BUILTIN,
	DEF_EXT_FRONT_END_LIB_BUILTIN): New macros.
	Declare the "unlocked" stdio functions.

	* c-common.c (c_expand_builtin_printf, c_expand_builtin_fprintf):
	Add an `unlocked' parameter and set the replacement function
	depending on it.
	(c_expand_builtin): Handle BUILT_IN_PRINTF_UNLOCKED and
	BUILT_IN_FPRINTF_UNLOCKED.

	* doc/extend.texi (printf_unlocked, fprintf_unlocked,
	fputs_unlocked): Document.

testsuite:
	* gcc.dg/format/builtin-1.c: Test unlocked stdio.
	* gcc.dg/format/c90-printf-3.c: Likewise.
	* gcc.dg/format/c99-printf-3.c: Likewise.
	* gcc.dg/format/ext-1.c: Likewise.
	* gcc.dg/format/ext-6.c: Likewise.
	* gcc.dg/format/format.h: Prototype unlocked stdio.

From-SVN: r48229