I added the whole OpenWatcom source a few days back to RDOS SVN repository. This means that now all the build tools for RDOS are included in the SVN. The only additional requirement is a prebuilt OpenWatcom distribution (not 1.9) that I will try to build shortly. Currently, I have a binary distribution at my web-site (http://www.rdos.net/openwatcom/rel2.zip) which is a snapshot with the required patches to the code generator missing in 1.9. RDOS repository is at http://www.rdos.net/svn
I decided to add the OpenWatcom source because their Perforce server now has been down for more than a week. Since RDOS now is so integrated (and requires) OpenWatcom, I think it was logical to add the source in case the official project dies.