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.
The patch makes (fundamentally) the same change to the src/control/control.c and src/pcm/pcm.c files from alsaLib, effecting the functions that handles the "ctl_type" and "pcm_type" configuration entries - usually defined in /etc/asound.conf or /home/user/.asoundrc . It adds the "libs" array to these entry types, so that multiple libs can be specified. These functions are trying to load a function from the plugin library for their entry (for example "ctl_type.pulse") so that it can be used by alsa.

If there is no libs array then alsaLib should behave exactly as normal, that is that it will try to open the function from the last "lib" entry, or it's own plugins dir if "lib" is not set. If the new "libs" array is set then alsa will now attempt to open the function from "lib" as well as "libs", it will only fail if none of the libraries specified can be opened, this means that 32bit alsa will ignore 64bit libs that it can't open, and won't fail/output errors providing that it finds a 32bit lib that it can open.

Docs on asound config files: http://git.alsa-project.org/?p=alsa-lib.git;a=blob;f=doc/asoundrc.txt