Support for `x86_64-unknown-linux-musl` target

[simongdavies]

#601 adds a couple of changes so that a use cab successfully build a hyperlight-host with the x86_64-unknown-linux-musl target.

We need to either test for this target or switch to it in our CI, if we decide to test for it we should probably do this periodcially and consider moving some of the tests that we do on each PR to a periodic basis (i.e. test against less targets during PR validation).

[danbugs]

Support exists, but we need a way to validate we don't regress it (e.g., add it in CI?). We'll discuss in v0.8.0.