Warning: You are using macOS 10.14.
We (and Apple) do not provide support for this old version.
It is expected behaviour that some formulae will fail to build in this old version.
It is expected behaviour that Homebrew will be buggy and slow.
Do not create any issues about this on Homebrew's GitHub repositories.
Do not create any issues even if you think this message is unrelated.
Any opened issues will be immediately closed without response.
Do not ask for help from MacHomebrew on Twitter.
You may ask for help in Homebrew's discussions but are unlikely to receive a response.
Try to figure out the problem yourself and submit a fix as a pull request.
We will review it but may or may not accept it.
I was going to edit this to make it more dramatic but I'm not sure how I can even do that. This is by far the most aggressive message I think a computer program has ever delivered to me. Clearly, the Homebrew developers really, really don't want to deal with people stuck on older versions of MacOS; the message repeats itself on almost every command run. In other news I've finally uninstalled Homebrew...