* builtins.def (BUILT_IN_FPRINTF): New entry.

	* c-common.c (c_expand_builtin_fprintf): New function.
	(init_function_format_info): Handle __builtin_fprintf.
	(c_common_nodes_and_builtins): Declare fprintf/__builtin_fprintf.
	(c_expand_builtin): Handle BUILT_IN_FPRINTF.

	* c-decl.c (duplicate_decls): Adjust comment.

	* extend.texi (fprintf): Document new builtin.

testsuite:
	* gcc.c-torture/execute/stdio-opt-3.c: New test.

From-SVN: r38788