I built the unstable branch of the ptlib -> opal -> ekiga chain. Unfortunately, without H.264 support, as opal and ekiga cannot detect the new x264 package included in the official repository.
ptlib - http://people.salixos.org/lmello/pkg/l/ptlib/
opal - http://people.salixos.org/lmello/pkg/l/opal/
ekiga - http://people.salixos.org/lmello/pkg/gnome/ekiga/
note - ekiga is slow on startup, but it works.