CI: stop testing x86_64-macos

There are two reasons for this:

1. Apple is about to drop support for this target. Zig will keep support
   but move it to a lower tier - one that does not require continuous CI
   testing. Support for this target will be maintained by the enthusiasm
   of contributors but will not block other bug fixes and enhancements.
2. This is our only non-self-hosted action runner. We are migrating away
   from GitHub soon at which point this runner will no longer be
   available.

.github/workflows/ci.yaml

@@ -50,15 +50,6 @@ jobs:
         uses: actions/checkout@v4
       - name: Build and Test
         run: sh ci/aarch64-linux-release.sh
-  x86_64-macos-release:
-    runs-on: "macos-13"
-    env:
-      ARCH: "x86_64"
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-      - name: Build and Test
-        run: ci/x86_64-macos-release.sh
   aarch64-macos-debug:
     runs-on: [self-hosted, macOS, aarch64]
     env:

ci/x86_64-macos-release.sh

@@ -1,75 +0,0 @@
-#!/bin/sh
-
-set -x
-set -e
-
-ZIGDIR="$PWD"
-TARGET="$ARCH-macos-none"
-MCPU="baseline"
-CACHE_BASENAME="zig+llvm+lld+clang-$TARGET-0.16.0-dev.104+689461e31"
-PREFIX="$HOME/$CACHE_BASENAME"
-JOBS="-j3"
-ZIG="$PREFIX/bin/zig"
-
-if [ ! -d "$PREFIX" ]; then
-  cd $HOME
-  curl -L -O "https://ziglang.org/deps/$CACHE_BASENAME.tar.xz"
-  tar xf "$CACHE_BASENAME.tar.xz"
-fi
-
-cd $ZIGDIR
-
-# Make the `zig version` number consistent.
-# This will affect the cmake command below.
-git fetch --unshallow || true
-git fetch --tags
-
-# Override the cache directories because they won't actually help other CI runs
-# which will be testing alternate versions of zig, and ultimately would just
-# fill up space on the hard drive for no reason.
-export ZIG_GLOBAL_CACHE_DIR="$PWD/zig-global-cache"
-export ZIG_LOCAL_CACHE_DIR="$PWD/zig-local-cache"
-
-# Test building from source without LLVM.
-cc -o bootstrap bootstrap.c
-./bootstrap
-./zig2 build -Dno-lib
-./zig-out/bin/zig test test/behavior.zig
-
-mkdir build
-cd build
-
-cmake .. \
-  -DCMAKE_PREFIX_PATH="$PREFIX" \
-  -DCMAKE_BUILD_TYPE=Release \
-  -DCMAKE_C_COMPILER="$ZIG;cc;-target;$TARGET;-mcpu=$MCPU" \
-  -DCMAKE_CXX_COMPILER="$ZIG;c++;-target;$TARGET;-mcpu=$MCPU" \
-  -DZIG_TARGET_TRIPLE="$TARGET" \
-  -DZIG_TARGET_MCPU="$MCPU" \
-  -DZIG_STATIC=ON \
-  -DZIG_NO_LIB=ON
-
-make $JOBS install
-
-stage3/bin/zig build test docs \
-  --zig-lib-dir "$PWD/../lib" \
-  -Denable-macos-sdk \
-  -Dstatic-llvm \
-  -Dskip-non-native \
-  --search-prefix "$PREFIX"
-
-# Ensure that stage3 and stage4 are byte-for-byte identical.
-stage3/bin/zig build \
-  --prefix stage4 \
-  -Denable-llvm \
-  -Dno-lib \
-  -Doptimize=ReleaseFast \
-  -Dstrip \
-  -Dtarget=$TARGET \
-  -Duse-zig-libcxx \
-  -Dversion-string="$(stage3/bin/zig version)"
-
-# diff returns an error code if the files differ.
-echo "If the following command fails, it means nondeterminism has been"
-echo "introduced, making stage3 and stage4 no longer byte-for-byte identical."
-diff stage3/bin/zig stage4/bin/zig