re PR middle-end/20109 (printf optimizations and non-ASCII character sets)

re PR middle-end/20109 (printf optimizations and non-ASCII character sets)

	PR middle-end/20109
	PR middle-end/25120
	* builtins.c (init_target_chars): New.
	(expand_builtin_printf, expand_builtin_fprintf,
	expand_builtin_sprintf, fold_builtin_sprintf,
	maybe_emit_sprintf_chk_warning, fold_builtin_sprintf_chk,
	fold_builtin_snprintf_chk, fold_builtin_printf,
	fold_builtin_fprintf): Check for matching format strings using
	the target charset.

testsuite:
	* gcc.dg/charset/builtin2.c: New test.

From-SVN: r107652