CMake build appears to be broken with CMake 3.18.2

[paul-elliott-arm]

Bug

OS
Probably all, tested with Linux.

Project does not appear to build with CMake 3.18.2, as it fails to find Python3, which is required for the test suites, and thus fails to configure.

As far as I can ascertain, this is an issue with CMake, and thus have reported the issue here on their gitlab, but I am opening this here to keep track of it.

I will submit a workaround patch to fix this for the time being, however this will be temporary until a better fix can be found.