So, after moving the trunk build to a different PC, it didn't run. It complained that the configuration was incorrect. (The dialog where you have to select all the executables.)
After further investigation, it seemed that the configuration of the previous install was messed up as well: it still used fpc 2.6.4, for example... So, I expect that the configuration on the previous pc is also incorrect.
Anyway, I rebuild everything and tried all the wiki said, deleted all configuration files of the previous installs, generated a fpc.cfg, but no matter where I place that, it is ignored. And it keeps complaining that everything is wrong: sources not found, rtl not found, no fpc.exe in the make.exe dir, etc.
So, where is the documentation or a working installer?