/usr/lib/libGLEWmx.so is in libglewmx1.5-dev 1.5.7.is.1.5.2-1ubuntu4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libGLEWmx.so.1.5.2
/usr/lib/libGLEWmx.so.1.5.2