100% static binary

[arkpar]

Support x86_64-unknown-linux-musl target build

[rainbreak]

I suppose there's two things here: 1) allow linking against musl, 2) enable a fully static binary. Linking against musl should make the fully static aim much easier, but there might be other problem libraries.

[MagaTailor]

Coming to ARM soon.

[eira-fransham]

I'm pretty certain that nanomsg relies on glibc extensions, so we'd have to remove our dependency on that. If you try to compile parity with a musl target you get missing definitions all over the place.

EDIT: It's more complicated than that, compiling nanomsg.rs with x86_64-unknown-linux-musl succeeds. It'd require more looking into.