[openal] Make OpenAL use ALSA PLUG:DMIX

[Roger]

>Definite evidence OpenAL alsoftrc is using plug:dmix previously when 
>specified!  I just don't think I see anything within DEBUG should plug:dmix is 
>actively being used, aside from that it's "Found".  In other words, 'Found 
>general:frequency = "44100"' as well, but further states an 
>"UpdateDeviceParams: Pre-reset: *Stereo, *Signed Short, *44100hz, 1024 update 
>size x4", and than a fail message.  So maybe when specifying an asoundrc 
>filter, an "UpdateDeviceParams: Using plug:dmix" notice should maybe be made?  
>Maybe just haven't coded yet, and similar to other sound driver plugins, as 
>upon notice of failure is the only mention within DEBUG was assumed sufficient 
>at the time.
>
>I will likely open a separate thread on the sample frequency 44100/48000hz 
>issue later.

I now know why 48000hz is being set regardless of what's stated within 
.alsoftrc, it is because ALSA plug:demix defaults to 48000hz when using 
plug:dmix.  I sort of knew ALSA defaults to 48000hz, but wanted to verify.

If a somebody wants another bit or sample rate, they'll need to fiddle with 
their .asoundrc or other ALSA configuration file.  48000hz seems to be best 
anyways, unless somebody is using an older slower computer.

(Verified with unsetting "device = plug:dmix" & setting "frequency = 44100" 
within the OpenAL alsoftrc file, and alongside having my asoundrc file 
restricting usage of ALSA plug:dmix.  44100hz was then accepted through my 
S/PDIF connected reciever, as specified within the OpenAL alsoftrc file, and 
further displayed within "ALSOFT_LOGLEVEL=3" and the recievers display.)

Now just to iron-out the details of FGCom not using ALSA plug:dmix.

-- 
Roger
http://rogerx.freeshell.org/