Mountain Lion doesn't include X11 any more, and XQuartz is the substitute. Having installed it, I see that XQuartz 2.7.2 installs in the non-standard (though commonly used) directory /opt. It also installs symlinks from /usr/X11 to /opt/X11.
I would prefer having XQuartz only use /usr/X11 and not create /opt/X11.
Is there a way to change the installation directory of XQuartz on Mountain Lion?