Should run XTS in CI
We should run (at least) XTS in libX11's CI pipeline, to catch issues like !31 (merged) before they escape into the wild.
Once we do so, we should clone that CI into a bunch of the other client libraries as well: ice, sm, xau, xaw, xcb, xext, xi, xmu, xpm, xt, and xtst. But first things first.