I have added a basic mingw64 meson workflow. The CI needs permission to allow that.
Permission granted. Could you rebase on current master, https://github.com/geany/geany/pull/3438 has only just been merged to allow manual start of the workflow :).
Thanks for the new workflow, this might help as a quick run of the Mingw build with Meson. It probably runs way faster than the full bloated Autotools build. I think this is a good addition to the existing Mingw workflow. Then we can replace the Autotools build some time in the future after we are confident that the Meson Mingw build is mature enough.