diff --git a/lwlib/lwlib-utils.c b/lwlib/lwlib-utils.c
index 9e535c1996d..1164482e182 100644
--- a/lwlib/lwlib-utils.c
+++ b/lwlib/lwlib-utils.c
@@ -17,6 +17,10 @@ You should have received a copy of the GNU General Public License
 along with GNU Emacs; see the file COPYING.  If not, write to
 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
 
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
 #include <X11/Xatom.h>
 #include <X11/IntrinsicP.h>
 #include <X11/ObjectP.h>