Fix github action (#2)

* Checkout submodules in github action
* Install Alex and Happy
* Split Hadrian building from the rest
* Enable parallel build
* Disable docs

.github/workflows/ci.yml

@@ -21,6 +21,8 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
+      with:
+        submodules: "recursive"
 
     - uses: haskell-actions/setup@v2
       id: setup
@@ -30,11 +32,20 @@ jobs:
         cabal-version: "latest"
         cabal-update: true
 
+    - name: Install Alex and Happy
+      run: |
+        cabal install alex
+        cabal install happy
+
     - name: Configure the build
       run: |
         ./boot
         ./configure
 
-    - name: Build
+    - name: Build Hadrian
+      run: |
+        ./hadrian/build --version
+
+    - name: Build the bindist
       run: |
-        ./hadrian/build --flavour=release binary-dist-dir
+        ./hadrian/build --flavour=release -j binary-dist-dir --docs=none