diff --git a/aegisub/libass/ass_drawing.c b/aegisub/libass/ass_drawing.c
index ee96bc0f2..be430ddd9 100644
--- a/aegisub/libass/ass_drawing.c
+++ b/aegisub/libass/ass_drawing.c
@@ -16,6 +16,8 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
+#include "config.h"
+
 #include <ft2build.h>
 #include FT_GLYPH_H
 #include FT_OUTLINE_H