haiku: Another attempt at fixing build.
diff --git a/src/locale/haiku/SDL_syslocale.cc b/src/locale/haiku/SDL_syslocale.cc
index a0885fa..3b930e8 100644
--- a/src/locale/haiku/SDL_syslocale.cc
+++ b/src/locale/haiku/SDL_syslocale.cc
@@ -19,6 +19,7 @@
3. This notice may not be removed or altered from any source distribution.
*/
+#include <AppKit.h>
#include <LocaleRoster.h>
#include <TypeConstants.h>