One of the common stigmas of cgo in Go projects is that it makes cross-compilation overly difficult. Its more difficult than pure Go projects, to be sure, but with the right shape of libraries and build scripts, it can be made to work well. libghostty is a good example of this. libghostty only depends on libc and the Zig compiler (tool, not language) as a drop-in replacement for c/c++ compilation means we can easily cross-compile! This commit adds documentation, tests, and examples on how to do this.