Minor enhancements

* hope physfs & openal-soft will be accepted in meta-oe / meta-multimedia [1-2]
* fix cross build for allegro4

By the way: What do you need allegro for - or do you need V4 of allegro. You might want to check [3]

[1] http://lists.linuxtogo.org/pipermail/openembedded-devel/2013-January/043418.html
[2] http://lists.linuxtogo.org/pipermail/openembedded-devel/2013-January/043419.html
[3] http://alleg.sourceforge.net/download.html

Andreas