Add macports support

[beryllium]

What does this PR do?

This PR attempts to add support for operating in a MacPorts environment, if detected & if a Homebrew environment is not found.

(I do not use Homebrew at all, so I was unable to use spc until I addressed this in my local checkout.)

I have a concern that this change may not play nicely on a system that has Homebrew but does not have MacPorts, as I was only able to test the inverse of that. Perhaps I should add a fixPort method that detects if brew is installed (preferably in a non-circular way), and no-ops the macports check failure? Or will the lack of a fixPort method accomplish this implicitly?

Also, this is branched off of v3, not feat/pgo-v3. Unsure if that complicates things, but hopefully it isn't an issue.

Checklist before merging

• If you modified *.php or *.yml, run them locally to ensure your changes are valid:
  • composer cs-fix
  • composer analyse
  • composer test
  • bin/spc dev:lint-config

[henderkes]

Generally looks good, but I don't have a mac to check if macports has recent enough versions of tools. Are they quick to update like brew?

[beryllium]

Generally looks good, but I don't have a mac to check if macports has recent enough versions of tools. Are they quick to update like brew?

There was a period of quite some time where their PHP coverage lagged behind, but now they have a dedicated maintainer for PHP stuff so it is much more responsive. Currently at 8.5.4 for their PHP 8.5 support (though PHP itself is at 8.5.6).

LLVM, as another example, is at 22.1.6, which matches the LLVM project itself.

[henderkes]

If they're at llvm 22 already I see no reason not to support macports.