When building for android, I am seeing a linker error because the build system is trying to pass an unsupported `-r` flag. I'm trying to build on macOS. Does wireguard-android need to be built on Linux (or with a gcc toolchain) right now, or is this an ndk issue, or a CMAKE configuration issue? Here's the abridged error:

ln -sfrt ./src/git.zx2c4.com/wireguard-go/ratelimiter/ ../wireguard-go/ratelimiter/ratelimiter.go; ... <many more>
ln: illegal option -- r
usage: ln [-Ffhinsv] source_file [target_file]
       ln [-Ffhinsv] source_file ... target_dir
       link source_file target_file

Thanks,
David