/usr/lib/gcc-cross/sh4-linux-gnu/8/libobjc.so is in libobjc-8-dev-sh4-cross 8-20180414-1ubuntu2cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/gcc-cross/sh4-linux-gnu/8/../../../../sh4-linux-gnu/lib/libobjc.so.4