Use musl libc for published binaries

We've fought with glibc versioning issues over time, and it's the reason for our docker dev environment being centos 6, as it's the oldest glibc (2.12) that has a c++17 toolchain backported to it. Finding a way to link against musl to avoid glibc would free us from having to use older distributions, and be able to use modern tools to produce binaries that could run on ancient systems.

(Filing to have an issue for this, as it's been discussed a few times, but without anything to track the idea.)

No files, tests, or entry points are named. Start by mapping how published binaries are built and how the CentOS 6 Docker development environment supplies the C++17 toolchain; done means producing binaries linked against musl that run on the targeted ancient systems.

Written by the indexing model from the issue text.