$OpenBSD: patch-src_output_c,v 1.4 2008/07/08 00:24:17 brad Exp $
--- src/output.c.orig	Sun May 14 16:40:35 2006
+++ src/output.c	Sun Jun 29 22:15:11 2008
@@ -501,7 +501,8 @@ output_skeleton (void)
   FILE *in;
   FILE *out;
   int filter_fd[2];
-  char const *argv[6];
+  char const *argv[7];
+  int i;
   pid_t pid;
 
   /* Compute the names of the package data dir and skeleton file.
@@ -512,7 +513,7 @@ output_skeleton (void)
   char *full_m4sugar;
   char *full_skeleton;
   char const *p;
-  char const *m4 = (p = getenv ("M4")) ? p : M4;
+  char const *m4 = (p = getenv ("M4")) ? p : "/usr/bin/m4";
   char const *pkgdatadir = (p = getenv ("BISON_PKGDATADIR")) ? p : PKGDATADIR;
   size_t skeleton_size = strlen (skeleton) + 1;
   size_t pkgdatadirlen = strlen (pkgdatadir);
@@ -534,12 +535,16 @@ output_skeleton (void)
     fprintf (stderr, "running: %s %s - %s\n",
 	     m4, full_m4sugar, full_skeleton);
 
-  argv[0] = m4;
-  argv[1] = full_m4sugar;
-  argv[2] = "-";
-  argv[3] = full_skeleton;
-  argv[4] = trace_flag & trace_m4 ? "-dV" : NULL;
-  argv[5] = NULL;
+  i = 0;
+  argv[i++] = m4;
+  if (strcmp(m4, "/usr/bin/m4") == 0) {
+       argv[i++] = "-g";
+  }
+  argv[i++] = full_m4sugar;
+  argv[i++] = "-";
+  argv[i++] = full_skeleton;
+  argv[i++] = trace_flag & trace_m4 ? "-dV" : NULL;
+  argv[i++] = NULL;
 
   init_subpipe ();
   pid = create_subpipe (argv, filter_fd);