diablod3 corrected me by pointing out that FreeCraft wasn't that, but had resumed under the name Stratagus. That's good news. I had visited that site, but wasn't really sure it they planned to continue FreeCraft or not, or that this was a continuation. Well, I checked out the sources, and this looks good.
And the FreeCraft 1.18 port for BeOS is now finished. Thanks to some pointers from jim4 at #stratagus I found out that the gzseek function on BeOS didn't work. That's unbelievable really. Luckily there was a function ready for an earlier release of zlib that didn't have gzseek. That function worked fine. I didn't have the energy to poor over the zlib sources to fix the bug there. Sorry.