Make it const everywhere.

src/conio/ciolib.c

@@ -81,7 +81,7 @@ CIOLIBEXPORT int directvideo=0;
 CIOLIBEXPORT int hold_update=0;
 CIOLIBEXPORT int puttext_can_move=0;
 CIOLIBEXPORT int ciolib_reaper=TRUE;
-CIOLIBEXPORT char *ciolib_appname=NULL;
+CIOLIBEXPORT const char *ciolib_appname=NULL;
 CIOLIBEXPORT int ciolib_initial_window_height = -1;
 CIOLIBEXPORT int ciolib_initial_window_width = -1;
 static int initialized=0;