/usr/lib/x86_64-linux-gnu/libGLU.so is in libglu1-mesa-dev 8.0.2-0ubuntu3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libGLU.so.1
/usr/lib/x86_64-linux-gnu/libGLU.so.1