I was having a hell of a time getting libquicktime installed. It just kept bombing out when trying to emerge it. It was somethign to do with opengl. If you get this problem try to do the following.
cp /usr/lib/opengl/xorg-x11/lib/libGL.la /usr/lib/opengl/ati/lib/libGL.la
cp /usr/lib/opengl/xorg-x11/lib/libGL.la /usr/lib/libGL.la
then try to emerge libquicktime
Should work, atleast it did for me. For some reason the libGL.la in the /usr/lib/ areas were empty files and causing this issue. Sometimes I really hate linux and the way things are empty and what not