[matthewCmatt]

Working toward #238

I believe this removes dependency on awk, but grep is still needed for elsewhere

I only tested this on the following.

# macOS ARM
% rustc --version --verbose | grep host | awk '{print $2}'
aarch64-apple-darwin
% rustc --print host-tuple
aarch64-apple-darwin

# linux x86
$ rustc --version --verbose | grep host | awk '{print $2}'
x86_64-unknown-linux-gnu
$ rustc --print host-tuple
x86_64-unknown-linux-gnu

# windows x86
> rustc --version --verbose | grep host | awk '{print $2}'
x86_64-pc-windows-msvc
> rustc --print host-tuple
x86_64-pc-windows-msvc

I also ran a build via just build-backstitch release on macOS and linux just for a sanity check.