$OpenBSD: patch-filter_c,v 1.4 2007/06/21 17:26:29 bernd Exp $
--- filter.c.orig	Sun Apr  1 23:58:55 2007
+++ filter.c	Sat Apr  7 11:40:27 2007
@@ -117,7 +117,7 @@ mutt_create_filter_fd (const char *cmd, FILE **in, FIL
       close (fderr);
     }
 
-    execl (EXECSHELL, "sh", "-c", cmd, NULL);
+    execl (EXECSHELL, "sh", "-c", cmd, (void *)NULL);
     _exit (127);
   }
   else if (thepid == -1)
