diff --git a/Makefile.in b/Makefile.in
index d737a1c3e..f45247565 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -60,6 +60,7 @@ HDRS = \
 	SDL_loadso.h \
 	SDL_log.h \
 	SDL_main.h \
+	SDL_messagebox.h \
 	SDL_mouse.h \
 	SDL_mutex.h \
 	SDL_name.h \