(check_effective_target_correct_iso_cpp_string_wchar_protos): New.
	* g++.dg/ext/builtin10.C: New test.

	* testsuite/21_strings/c_strings/char/3.cc: New test.
	* testsuite/21_strings/c_strings/wchar_t/3.cc: New test.

From-SVN: r143865