Shared libraries

Eh, we make tarballs that extract to a standard installation prefix. The binaries are relocatable, so we just need to make sure we build on a suitably old distro (currently CentOS8) and document libraries we assume exist (X11, some libxcb libraries, etc.). Works well enough. But yes, if you don't want to ship everything above the "bare bones", you'll need a per-distro package.