/usr/lib/gcc-cross/powerpc-linux-gnuspe/6/libgcc_s.so.1 is in libgcc-6-dev-powerpcspe-cross 6.3.0-18cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/gcc-cross/powerpc-linux-gnuspe/6/../../../../powerpc-linux-gnuspe/lib/libgcc_s.so.1