(svn r17534) -Codechange: unify the naming of callback masks/flags

src/newgrf_callbacks.h

@@ -262,6 +262,13 @@ enum HouseCallbackMask {
 	CBM_HOUSE_DENY_DESTRUCTION          = 10, ///< conditional protection
 };
 
+/**
+ * Callback masks for canals.
+ */
+enum CanalCallbackMask {
+	CBM_CANAL_SPRITE_OFFSET       = 1, ///< Enable add sprite offset callback
+};
+
 /**
  * Callback masks for cargos.
  */