If you're seeing good support for musl, I'd be interested in receiving a patch to add it as another combination. I prefer to keep the libc apart from the kernel (the mistake we made long ago was to mix them) so that we don't have issues anymore when building on other libcs. For example getaddrinfo tends to be bogus on uClibc and must not be enabled there. And threads do not work on dietlibc if I remember well.