/usr/lib/gcc-cross/powerpc64-linux-gnu/5/libobjc.so is in libobjc-5-dev-ppc64-cross 5.5.0-12ubuntu1cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/gcc-cross/powerpc64-linux-gnu/5/../../../../powerpc64-linux-gnu/lib/libobjc.so.4