The old "meson build" build command was actually deprecated a few months ago*. It turns out that you're supposed to use "meson setup build" instead which has been around for years. Go ahead and be a good citizen and update this in the CI. Also replace any mention of "meson build" with "meson setup build" in the documentation as well and change the one random hardcoded string we have in meson.build to "meson configure build" (might as well). *: https://github.com/mesonbuild/meson/commit/3c7ab542c0c4770241eae149b0d4cd8de329aee0