Can't build golang packages with pmbootstrap
It's currently not possible to build golang packages in pmbootstrap for any architecture that's crosscompiled. Binaries compiled by golang use CPU instructions that are not supported in qemu user-mode emulation and the go compiler is also a go binary.
golang can crosscompile on its own though so we really only need a way to mark go packages for native compiling like the linux kernel and setting the correct environment variables for the go compiler.
$ GOOS=linux GOARCH=arm64 go build package-import-path