* Add WITH_FFMPEG knob
* Add WITH_SPEEX knob to build with speex-devel instead of the bundled version
NOTE: there is an explicit BUILD_DEPENDS to make sure audio/speex-devel
is installed as audio/speex and audio/speex-devel install the same shared
library version!!
PR: 95464
Submitted by: Joerg Pulz <Joerg.Pulz@frm2.tum.de>
Approved by: maintainer
