Added parallel build to workflow

Using a matrix and job separation we can make the architectures compile
parallel to eachother, hopefully reducing the time required for builds
and also simplifying the process of building a single architecture.

Also modified the pipeline to only upload artifacts if we later use them
to create a release (I.e, only upload artifacts on tag push actions).

Author: roddyrap

.github/workflows/pipeline.yaml

@@ -10,8 +10,11 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        architecture: ["x86_64", "arm", "aarch64", "powerpc", "mips", "mipsel"]
 
+    runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
       with:
@@ -21,19 +24,32 @@ jobs:
       run: sudo apt-get install -y wget
 
     - name: Build
-      run: make build -j$((`nproc`+1))
+      run: make build-${{ matrix.architecture }} -j$((`nproc`+1))
 
+    # We only need to create & upload artifacts if we are creating a new version.
     - name: Pack
-      run: make pack
+      if: github.event_name == 'push'
+      run: make pack-${{ matrix.architecture }}
 
     - name: Upload artifact
       uses: actions/upload-artifact@v4
+      if: github.event_name == 'push'
       with:
         name: gdb-static
         path: build/artifacts/gdb-static*.tar.gz
 
-    - name: Publish release
-      if: github.event_name == 'push'
-      uses: softprops/action-gh-release@v2
-      with:
-        files: build/artifacts/gdb-static*.tar.gz
+  create_and_publish_release:
+    runs-on: ubuntu-latest
+    needs: build
+    if: github.event_name == 'push'
+
+    steps:
+      - name: Download build artifacts
+        uses: actions/download-artifact@v4
+        with:
+          path: "build-results/"
+
+      - name: Publish release.
+        uses: softprops/action-gh-release@v2
+        with:
+          files: build-results/*