/usr/lib/gcc-cross/powerpc-linux-gnuspe/8/libobjc.so is in libobjc-8-dev-powerpcspe-cross 8-20180414-1ubuntu2cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/gcc-cross/powerpc-linux-gnuspe/8/../../../../powerpc-linux-gnuspe/lib/libobjc.so.4