diff --git a/Makefile.am b/Makefile.am
index 55d3b16f..cb8256fe 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,7 +1,7 @@
 
 AM_CPPFLAGS = -Isrc -DCONFIG_DATADIR=\"@datadir@\"
 AM_CPPFLAGS += -I../src # work around some bug in make distcheck
-AM_LFLAGS = -i
+AM_LFLAGS = -i -D_GNU_SOURCE=1
 #AM_COLOR_TESTS = no
 #LDFLAGS =
 #LDADD =
diff --git a/src/meta/debug.c b/src/meta/debug.c
index 8482a323..3509722f 100644
--- a/src/meta/debug.c
+++ b/src/meta/debug.c
@@ -1,6 +1,7 @@
 
 #line 3 "src/meta/debug.c"
 
+#define _GNU_SOURCE 1
 #define  YY_INT_ALIGNED short int
 
 /* A lexical scanner generated by flex */
@@ -1135,7 +1136,7 @@ extern void fb_sha1();
   (? | h{elp})
 */
 
-#line 1139 "src/meta/debug.c"
+#line 1140 "src/meta/debug.c"
 
 #define INITIAL 0
 
@@ -1357,7 +1358,7 @@ YY_DECL
 
 
 
-#line 1361 "src/meta/debug.c"
+#line 1362 "src/meta/debug.c"
 
 	while ( 1 )		/* loops until end-of-file is reached */
 		{
@@ -2537,7 +2538,7 @@ YY_RULE_SETUP
 #line 977 "src/meta/debug.l"
 ECHO;
 	YY_BREAK
-#line 2541 "src/meta/debug.c"
+#line 2542 "src/meta/debug.c"
 case YY_STATE_EOF(INITIAL):
 	yyterminate();