Enhanced OpenGL port of the official DOOM source code that also supports
Heretic, Hexen, and Strife.

Optional compile-time dependency: fluidsynth (autodetected).

See README_SBo.txt for optional runtime dependencies.

*Note: if you're upgrading from gzdoom-1.5.x, the config file location
has changed. To keep your old settings:

  mkdir -p ~/.config/gzdoom
  cp ~/.gzdoom/zdoom.ini ~/.config/gzdoom
