small note that now msys2 is 64bit

INSTALL.txt

@@ -15,8 +15,8 @@ VERY IMPORTANT INSTALLATION ISSUES!
 ***********************************
 
 Note: 
-The master version will not work on 32bit computers and operating systems.
-Use the old OMDev for that, branch: OM116maintenance
+The master version will *only work* on 64bit computers and operating systems.
+If you have a 32bit computer, use the old OMDev, branch: OM116maintenance
 
 MSYS setting
 ============