Download powerpc-unknown-linux-musl-gcc
toolchain from here - https://musl.cc/#binaries.
Unpack and add the installation path to PATH env variable.
powerpc-unknown-linux-musl-gcc --version
Run powerpc-musl-build.sh.
Also, you can pass addtional cargo options to it.
./powerpc-musl-build.sh --examples my_cool_example