Issue with brew package pkgconf

[xavierleroy]

On macos-latest, I'm getting:

+ /opt/homebrew/bin/brew "install" "pkgconf"
[ERROR] System package install failed with exit code 1 at command:
- ==> Downloading https://ghcr.io/v2/homebrew/core/pkgconf/manifests/2.3.0
            brew install pkgconf
- ==> Fetching pkgconf
- ==> Downloading https://ghcr.io/v2/homebrew/core/pkgconf/blobs/sha256:4d7c5803943bf2dcc8cb9ff8c838ea4283eeab24f49982df044cbc3031856fd8
- ::error::Cannot install pkgconf because conflicting formulae are installed.%0A  pkg-config: because both install `pkg.m4` file%0A%0APlease `brew unlink pkg-config` before continuing.%0A%0AUnlinking removes a formula's symlinks from /opt/homebrew. You can%0Alink the formula again after the install finishes. You can `--force` this%0Ainstall, but the build may fail or cause obscure side effects in the%0Aresulting software.%0A
[ERROR] These packages are still missing: pkgconf

It could be that the macOS runners now have the pkg-config brew package already installed, which conflicts with the pkgconf package that setup-ocaml wants to install.

A simple solution would be for setup-ocaml to use the pkg-config package instead of pkgconf.

[smorimoto]

Probably it's related to this change: Homebrew/homebrew-core#194885

[smorimoto]

I raised the issue upstream: actions/runner-images#10984