Advanced Linux Sound Architecture (known by the acronym ALSA) is a linux kernel component intended to replace the original Open Sound System (OSS) for providing device drivers for sound cards.
For more information on alsa, visit http://en.wikipedia.org/wiki/Advance...d_Architecture.
If you get the error
checking for snd_pcm_open in -lasound... no configure: error: Ogg or Wave support on Linux requires the alsa library
while building firefox on linux, it means a few library files required for ogg or wave support are missing.
Quick Way around
You can append the following lines to your .mozconfig:
ac_add_options --disable-ogg ac_add_options --disable-wave