* dlltool.c (set_dll_name_from_def): New function. Strip name

	* dlltool.c (set_dll_name_from_def): New function.  Strip name
	to basename, with warning.
	(def_name): Use it.
	(def_library): Likwise.
	(main): Strip arg of --dllname to basename, with warning.
	Only use basename of exp_name when inferring dll_name.