/usr/powerpc-linux-gnu/lib/libgnatprj.so is in libgnatprj5-dev-powerpc-cross 5.3.1-14ubuntu2cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/powerpc-linux-gnu/lib/libgnatprj.so.5
/usr/powerpc-linux-gnu/lib/libgnatprj.so.5