common.c:	public functions for both the backend and the frontend.		requires conv.c and wchar.cconv.c:		static functions and a public table for code conversionwchar.c:	mostly static functions and a public table for mb string and		multi-byte conversionmbutilc.c:	public functions for the backend only.		requires conv.c and wchar.cwstrcmp.c:	strcmp for mbwstrncmp.c:	strncmp for mbvarable.c:	public functions for show/set/reset variable commands