GitHub Action: "Tail calling interpreter" & JIT times out after 60 minutes on macOS x86_64 on building LLVM from source #159612

##[warning]You are using macOS on Intel x86_64.
We do not provide support for this platform (as-of September 2026, announced August 2025).

Apple have dropped Intel x86_64 support in macOS Golden Gate (27).
GitHub Actions are dropping macOS Intel x86_64 runners in 2027.
Homebrew is a non-profit project run entirely by volunteers, not employees.
If the biggest companies in the world cannot support macOS Intel x86_64
any longer, sadly neither can we.

Homebrew no longer builds bottles for this configuration.
Existing bottles may still work, but updated formulae may build from source.
==> Downloading bottle manifests
✔︎ Bottle Manifest llvm@21 (21.1.8)
==> Would install 1 formula:
llvm@21 21.1.8
==> Would upgrade 1 dependency for llvm@21:
xz
==> Downloading https://raw.githubusercontent.com/Homebrew/homebrew-core/1d8ebe59e0fe1e7e213ee99dda5643993a66b1d1/Formula/x/xz.rb
Already downloaded: /Users/runner/Library/Caches/Homebrew/downloads/a65becd715f339f0764495d746d9770a97f413dd9898cf267542424fb0b7cfdd--xz.rb
==> Fetching downloads for: llvm@21
✔︎ API Source xz.rb
✔︎ Formula xz (5.8.4)
✔︎ Bottle llvm@21 (21.1.8)
==> Pouring llvm@21--21.1.8.sonoma.bottle.tar.gz
##[warning]llvm@21 was installed but not linked because llvm@20 is already installed.
To link this version, run:
  brew link llvm@21

🍺  /usr/local/Cellar/llvm@21/21.1.8: 8,670 files, 1.6GB
==> Caveats
==> llvm@21

==> Fetching downloads for: llvm@21
✔︎ API Source llvm@21.rb
✔︎ API Source xz.rb
✔︎ Formula xz (5.8.4)
✔︎ API Source cmake.rb
✔︎ Formula cmake (4.4.4)
✔︎ API Source readline.rb
✔︎ Patch readline83-001
✔︎ Patch readline83-002
✔︎ Patch readline83-003
✔︎ Patch readline83-004
✔︎ Patch readline83-005
✔︎ Patch readline83-006
✔︎ Formula readline (8.3.6)
✔︎ API Source sqlite.rb
✔︎ Formula sqlite (3.54.0)
✔︎ API Source pkgconf.rb
✔︎ Formula pkgconf (3.0.8)
✔︎ API Source python@3.15.rb
✔︎ Resource python@3.15--flit-core
✔︎ Resource python@3.15--pip
✔︎ Formula python@3.15 (3.15.0)
✔︎ Patch 0140-llvm-no-cmp-spec.patch
✔︎ Patch 0141-infinity_nan.patch
✔︎ Patch 477a65a051ce151895193f8dede1262fdc251132.patch?full_index=1
✔︎ Formula llvm@21 (21.1.8)
==> Installing dependencies for llvm@21: cmake, readline, sqlite, xz, pkgconf and python@3.15
==> Upgrading llvm@21 dependency: cmake (4.4.2 -> 4.4.4)
==> ./bootstrap --prefix=/usr/local/Cellar/cmake/4.4.4 --no-system-libs --parall
==> make
==> make install