* utils/hbmk2/hbmk2.prg
+ In incremental (-inc) mode .c and .rc stubs are now created
inside workdir and kept there for consecutive build runs.
They are only recreated if necessary. This means that
-gt, -main= and -icon options work well with -inc mode, and
won't anymore force linking on each run.
* All stubs will be recreated in -rebuild mode.
* Above stubs will be deleted in -clean mode. (except vcshead and tshead)