"LIBS" in the final fsxs script will be empty now.
We still link against libfreeswitch when building a module,
but we don't explicitly list (some of) its dependency libs anymore
(this list was not complete anyway).

This fixes a bogus /path_to_source/expat.la entry in LIBS that
came from "apu-config --libs".

Tested on Gentoo x86_64 (binutils 2.20.1) and Centos 5.5 (binutils 2.17.50).
Tested-by: Stefan Knoblich <s.knoblich@axsentis.de>
Signed-off-by: Stefan Knoblich <s.knoblich@axsentis.de>