diff --git a/src/udev-seat.c b/src/udev-seat.c
index 927bb7a4..a8790b3f 100644
--- a/src/udev-seat.c
+++ b/src/udev-seat.c
@@ -20,6 +20,8 @@
  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
+#include "config.h"
+
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>