Dropping the MIR backend from GTK 3.24

We are thinking of dropping the MIR backend from GTK 3.24.

Apparently, it hasn’t been built since 2017, as one of its dependencies hasn’t been updated; the MIR backend hasn’t been built on Ubuntu since early 2018 because of that either.

I suppose people using Ubuntu LTS before 18.04 may still use it, but those won’t be affected by a change in GTK 3.24 anyway.

If people are using the MIR backend and GTK 3.24, this would be a good time to speak up.

The MIR backend has been removed now. This means 3.24.12 will no longer include it.