--- pine/osdep/pipe
+++ pine/osdep/pipe
@@ -266,7 +266,7 @@
 		shellpath[sizeof(shellpath)-1] = '\0';
 	    }
 
-	    execl(shellpath, shell, command ? "-c" : 0, command, 0);
+	    execl(shellpath, shell, command ? "-c" : NULL, command, NULL);
 	}
 
 	fprintf(stderr, "Can't exec %s\nReason: %s",