Pulseaudio support for 32bit alsa app playback on 64bit linux.

Background: http://thread.gmane.org/gmane.linux.distributions.nixos/3435

On x86_64, alsaLib loads a 64bit lib from /etc/asound.conf for playback via pulseaudio, then 32bit apps (such as wine) fail to load the lib. Alsa doesn't include a way to try multiple libraries, so there is no way to specify 32bit/64bit libs at the same time. This patch adds a 'libs' array entry to asound config files so that any number of libraries can be specified in asound config files. Alsa will try to open all of them, allowing libraries for multiple archs to be specified.

Fixes wine audio playback via pulseaudio on "x86_64-linux".

* Possible Mass Rebuild - Rebuilds anything that depends on alsaLibs (-> pulseaudio), about 1.5k packages including most large applications.
This is a pretty big patch. Can you explain a bit what it does, please?