diff --git a/build/aclocal/gtk.m4 b/build/aclocal/gtk.m4
index f2dd472197..b8cf4024af 100644
--- a/build/aclocal/gtk.m4
+++ b/build/aclocal/gtk.m4
@@ -4,7 +4,7 @@
 dnl AM_PATH_GTK([MINIMUM-VERSION, [ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND [, MODULES]]]])
 dnl Test for GTK, and define GTK_CFLAGS and GTK_LIBS
 dnl
-AC_DEFUN([AM_PATH_GTK],
+AC_DEFUN(AM_PATH_GTK,
 [dnl 
 dnl Get the cflags and libraries from the gtk-config script
 dnl