Unintended linkage to llvm's libunwind via gdal has broken gz-common5 bottles built with Xcode 15

[scpeters]

As mentioned in Homebrew/homebrew-core#164034, there is an issue with the linker in Xcode 15 that causes unintended linking to llvm's libunwind if it is in the library search paths. This widely affects lots of formulae (as noted in Homebrew/homebrew-core#169354 (comment)) to the extent that a workaround is being planned in Homebrew/brew#17104. This currently affects gz-common5 and dependents.

It was tricky to diagnose because it only affects our macOS Ventura bottles, and not Monterey:

• built on mac-six.ventura: https://build.osrfoundation.org/view/gz-garden/job/gz_common5-install_bottle-homebrew-amd64/127/
• built on mac-five.monterey: https://build.osrfoundation.org/view/gz-garden/job/gz_common5-install_bottle-homebrew-amd64/128/

Brew linkage test result

+ brew linkage --test gz-common5
Broken dependencies:
  /usr/local/opt/llvm/lib/libunwind.1.dylib (llvm)
Build step 'Execute shell' marked build as failure

Checklist

• Identify change in homebrew-core that broke the bottle
  • ???
• Identify list of affected formulae
  • gz-common5 and dependents
• Remove broken bottles: for each affected formula, run brew bump-revision --remove-bottle-block
  • remove affected ventura bottles gz-common5, dependents: remove ventura bottle #2640
• Wait for extend/ENV/super: avoid adding llvm to HOMEBREW_LIBRARY_PATHS Homebrew/brew#17104 to land
• Rebuild broken bottles
  • gz-common5: revision bump for llvm #2643
  • Garden Rebuild garden bottles for llvm #2645
  • Harmonic Rebuild harmonic bottles for llvm #2644