fix(ci): Try to fix expat.

.github/workflows/validate-pr.yml

@@ -13,6 +13,11 @@ jobs:
       - uses: actions/checkout@v2
       - name: Install esy
         run: npm install -g esy
+        # * BSD / macOS >=10.7 (arc4random_buf): HAVE_ARC4RANDOM_BUF,
+        # * BSD / macOS <10.7 (arc4random): HAVE_ARC4RANDOM
+      - name: Install native dependencies on macos-latest
+        run: brew install arc4random_buf
+        if: matrix.os == 'macos-latest'
       - name: Setup Git to push back
         run: |
           git remote set-url --push origin https://$GITHUB_ACTOR:[email protected]/$GITHUB_REPOSITORY
@@ -84,7 +89,11 @@ jobs:
       - uses: actions/checkout@v2
       - name: Install esy
         run: npm install -g esy
-      - run: brew install coreutils
+        # * BSD / macOS >=10.7 (arc4random_buf): HAVE_ARC4RANDOM_BUF,
+        # * BSD / macOS <10.7 (arc4random): HAVE_ARC4RANDOM
+      - name: Install native dependencies on macos-latest
+        run: brew install coreutils arc4random_buf
+        if: matrix.os == 'macos-latest'
       - name: Solve doc dependencies
         run: esy @doc install
       - name: Print esy cache
@@ -178,6 +187,11 @@ jobs:
       - uses: actions/checkout@v2
       - name: Install esy
         run: npm install -g esy
+        # * BSD / macOS >=10.7 (arc4random_buf): HAVE_ARC4RANDOM_BUF,
+        # * BSD / macOS <10.7 (arc4random): HAVE_ARC4RANDOM
+      - name: Install native dependencies on macos-latest
+        run: brew install arc4random_buf
+        if: matrix.os == 'macos-latest'
       - name: Install native dependencies on ubuntu-latest
         if: matrix.os == 'ubuntu-latest'
         run: |