[quake2] Fwd: ALSA sound support

[Jamie Wilkinson]

This one time, at band camp, Jay Dolan wrote:
>11238, I don't believe Icculus suffers from the mod
>loading defficiency that was present in Q2F.  However,
>exporting QUAKE2_HOME to the environment, as seen in
>the latter half of the diff, can make it easier for
>new mods to perform file io in their respective homes.

This is due to the change in build architecture on q2f, IIRC (for better or
worse).  icculus q2 stuck with id's build system.