$OpenBSD: patch-gcc_dbxout_c,v 1.2 2011/01/13 00:18:18 jeremy Exp $
--- gcc/dbxout.c.orig	Thu May 20 22:58:44 2010
+++ gcc/dbxout.c	Mon Jan 10 12:49:16 2011
@@ -1140,7 +1140,7 @@ dbxout_init (const char *input_file_name)
 	  if (cwd[0] == '\0')
 	    cwd = "/";
 	  else if (!IS_DIR_SEPARATOR (cwd[strlen (cwd) - 1]))
-	    cwd = concat (cwd, "/", NULL);
+	    cwd = concat (cwd, "/", (void *)0);
 	}
 #ifdef DBX_OUTPUT_MAIN_SOURCE_DIRECTORY
       /* APPLE LOCAL ss2 */
