Since release simutrans-112.2 the simutrans-src-112.2.zip does not contain the directories config, font, music and text as in previous released source archives. To run the game the files in that directories are mandatory. To get simutrans-112.2 running, I extracted the missing directories from binary release and copy to /usr/share/games/simutrans. To reproduce: uninstall previous installation of simutrans remove /usr/share/games/simutrans run emerge simutrans try starting simutrans simutrans tells about missing font/prop.fnt
simutrans-0.112.3 should have that fixed.
Confirmed simutrans-0.112.3 compiles/install/runs