Built from source, again using the Salix package build system. Here's the a link to the source.
http://code.google.com/p/libass/downloads/
and the configuration options that I used.
./configure --prefix=/usr /
--libdir=/usr/lib${LIBDIRSUFFIX} /
--localstatedir=/var /
--sysconfdir=/etc /
--disable-static /
--build=$arch-slackware-linux
There will be a few more like xvidcore, opus libvpx which I built from source. If it's not available from slackwarearm repo then I built it from source