[HB] Add FixedVersion cast to int

src/hb-ot-layout-open-private.h

diff --git a/src/hb-ot-layout-open-private.h b/src/hb-ot-layout-open-private.h
index 0955c6f..91aacfc 100644
--- a/src/hb-ot-layout-open-private.h
+++ b/src/hb-ot-layout-open-private.h
@@ -293,6 +293,8 @@
 
 struct FixedVersion
 {
+  inline operator uint32_t(void) const { return major << 16 + minor; }
+
   SHORT  major;
   USHORT minor;
 };