[AD] Windows sound config

["Ben Davis" <ben@xxxxxxxxxx>]

In DOS, install_sound() will use information from allegro.cfg to decide on
quality, volume, etc. I tested this with quality and digi_volume, and it
worked.

When I did the same thing in Windows, *using DIGI_DIRECTAMX(0)*, it failed
to read the config file. The quality was always the same (I believe it was
using quality = 1).

This is in response to a thread on allegro.cc, where someone else was having
the same problem.

Looking at the source (src/win/wdsndmix.c, src/sound.c and src/mixer.c), I
couldn't see why this was failing.

In src/mixer.c, the _sound_hq variable is responsible for sound quality.

In src/win/wdsndmix.c, there's loads of DirectX stuff I don't understand,
then a call to _mixer_init() from src/mixer.c. _sound_hq is not modified
anywhere.

In src/sound.c, install_sound() calls read_sound_config().
read_sound_config() uses the standard config functions to read _sound_hq
from the file.

I don't have the facilities to investigate this further (I'm a DOS
programmer really :-P). Can someone look into this please?

Thanks,

Ben Davis