* cppfiles.c (cpp_make_system_header): New function.
	* cpplib.h: Prototype it.
	* cpplib.c (do_line, do_pragma_system_header): Use it.
	* fix-header.c (read_scan_file): Use it.

	* fix-header.c (check_macro_names): Cast second arg of
	cpp_defined to const unsigned char *.
	(read_scan_file): Make getchar_call const unsigned char.

From-SVN: r34641