# dpkg --force-all --configure libgl1-mesa-glx
Setting up libgl1-mesa-glx (7.10.2-0ubuntu2.1) ...
update-alternatives: error: alternative link /usr/lib/xorg/extra-modules is already managed by x86_64-linux-gnu_gl_conf.
dpkg: error processing libgl1-mesa-glx (--configure):
 subprocess installed post-installation script returned error exit status 2
Errors were encountered while processing:
 libgl1-mesa-glx