The master branch reflects the upstream musl without any modifications. Other branches are used for WebAssembly-specific experiments.
The prototype branches are just that: experimental prototypes.
Don't commit to the master branch except to update from musl!
To update the master branch:
git clone --origin wasm git@github.com:WebAssembly/musl.git
cd musl
git remote add musl git://git.musl-libc.org/musl
git remote -v # List all remotes.
git checkout master
git pull musl master
git push wasm master
Consult musl's readme and license for further information.