--- fontforgeexe/startui.c.orig
+++ fontforgeexe/startui.c
@@ -64,6 +64,10 @@ extern uninm_blocks_db blocks_db;
 
 #ifdef __Mac
 extern void setup_cocoa_app();
+
+/* add missing def on older MacOS systems */
+typedef long SRefCon;
+
 #endif
 
 #ifdef _NO_LIBPNG