This changes our handmade `configure` calls to rely on the streamlined build
process from `godot-mono-builds`, so that our builds are consistent with the
ones generated there.
This enables us to target macOS arm64 easily as neikeq did the relevant work
in the `godot-mono-builds` scripts.
Includes a backport of https://github.com/mono/mono/pull/21147 to fix Mono
build with `godot-mono-builds` using a wrapper for osxcross.
Rémi Verschelde