The current stable version of openal (1.5.30) has no vorbis useflag, so portage falsely wants to downgrade openal to 0.0.8-r2. "Falsely", because on my system ultimatestunts works (and produces sound) with openal-1.5.30 (without vorbis useflag since it does not exist). So I guess that the correct dependency should be something like || ( >=media-libs/openal-1.5 media-libs/openal[vorbis] )
*** This bug has been marked as a duplicate of bug 249966 ***