Fix typo :)
diff --git a/src/hb-config.hh b/src/hb-config.hh
index 19ceed8..56c85a0 100644
--- a/src/hb-config.hh
+++ b/src/hb-config.hh
@@ -62,7 +62,7 @@
 #define HB_NO_MATH
 #define HB_NO_MMAP
 #define HB_NO_NAME
-#define HB_NO_OEPN
+#define HB_NO_OPEN
 #define HB_NO_SETLOCALE
 #define HB_NO_SUBSET_LAYOUT
 #endif