$OpenBSD$
--- src/display.c.orig	Wed Sep 17 00:00:43 2008
+++ src/display.c	Wed Sep 17 00:07:17 2008
@@ -158,13 +158,13 @@ display_open (char *prog, int no_xterm, int flash_sz, 
         if (no_xterm)
         {
             execlp (prog, prog, "--pfd", spfd, fl_sz, sr_sz, sr_start, eep_sz,
-                    NULL);
+                    (void *)NULL);
         }
         else
         {
             /* try to start up the display program in it's own xterm */
             execlp ("xterm", "xterm", "-geom", "100x50", "-e", prog, "--pfd",
-                    spfd, fl_sz, sr_sz, sr_start, eep_sz, NULL);
+                    spfd, fl_sz, sr_sz, sr_start, eep_sz, (void *)NULL);
         }
 
         /* if the exec returns, an error occurred */
