Add PG_RETURN_UINT16 macro.

Manuel Kniep

src/include/fmgr.h

@@ -298,6 +298,7 @@ extern struct varlena *pg_detoast_datum_packed(struct varlena * datum);
 #define PG_RETURN_INT32(x)	 return Int32GetDatum(x)
 #define PG_RETURN_UINT32(x)  return UInt32GetDatum(x)
 #define PG_RETURN_INT16(x)	 return Int16GetDatum(x)
+#define PG_RETURN_UINT16(x)	 return UInt16GetDatum(x)
 #define PG_RETURN_CHAR(x)	 return CharGetDatum(x)
 #define PG_RETURN_BOOL(x)	 return BoolGetDatum(x)
 #define PG_RETURN_OID(x)	 return ObjectIdGetDatum(x)