The rss-glx screensaver package includes a fireworks screensaver called
skyrocket.
At configure, it checks for the OpenAL sound library to enable audio effects in
skyrocket.
It should therefore have a local useflag and conditional dependency on
media-libs/openal.
/usr/portage/profiles/use.local.desc:
+x11-misc/rss-glx:openal - Enables Open Audio Library support in rss-glx
Skyrocket screensaver
/usr/portage/x11-misc/rss-glx/rss-glx.0.7.6.ebuild:
-IUSE="kde sse 3dnow"
+IUSE="kde sse 3dnow openal"
...
+ openal? ( media-libs/openal )