diff -up groff-1.18.1.4/src/devices/grolbp/lbp.cc.old groff-1.18.1.4/src/devices/grolbp/lbp.cc
--- groff-1.18.1.4/src/devices/grolbp/lbp.cc.old	2008-01-03 15:38:25.000000000 +0100
+++ groff-1.18.1.4/src/devices/grolbp/lbp.cc	2008-01-03 15:38:33.000000000 +0100
@@ -25,7 +25,9 @@ TODO
 
  - Add X command to include bitmaps
 */
-#define _GNU_SOURCE
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE 1
+#endif
 
 #include "driver.h"
 #include "lbp.h"