This is a bootloader for Open Firmware PowerPC systems that we will use
to replace grub-ieee1275 in device-generic-ppc64le. Due to its use of
RUSTC_BOOTSTRAP, this APKBUILD cannot go to Alpine at the moment, but
once the Rust targets are added upstream, this can be moved to aports.
Part-of: <https://gitlab.postmarketos.org/postmarketOS/pmaports/-/merge_requests/9002>
