Use Homebrew to install LLVM

.github/workflows/build.yml

@@ -14,21 +14,9 @@ jobs:
       # https://github.com/marketplace/actions/setup-bazelisk
       - name: install bazelisk
         uses: bazelbuild/setup-bazelisk@v2
-      # https://github.com/marketplace/actions/install-llvm-and-clang
-      - name: Cache LLVM and Clang, Mount bazel cache
-        id: cache-llvm
-        uses: actions/cache@v3
-        with:
-          path: |
-            C:/Program Files/LLVM
-            ./llvm
-            ~/.cache/bazel
-          key: llvm-3.5
-      - name: Install LLVM and Clang
-        uses: KyleMayes/install-llvm-action@v1
-        with:
-          version: "14.0"
-          cached: ${{ steps.cache-llvm.outputs.cache-hit }}
+      - name: install llvm
+        # Must be Homebrew; GitHub Action's LLVM install doesn't work :/
+        run: brew install llvm
       - name: build lol
         run: |
           bazel build //explorer