1 files changed, 1 insertions, 1 deletions

diff --git a/src/alloc.c b/src/alloc.c
index 0f81c943ad3..7598386ebca 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -5015,7 +5015,7 @@ returns nil, because real GC can't be done.  */)
 
 #ifdef USE_GTK
   {
-    extern void xg_mark_data ();
+    extern void xg_mark_data (void);
     xg_mark_data ();
   }
 #endif