/usr/bin/mipsel-linux-gnu-gnatgcc is in gnat-8-mipsel-linux-gnu 8-20180414-1ubuntu2cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/bin/mipsel-linux-gnu-gcc-8
/usr/bin/mipsel-linux-gnu-gcc-8