ci: Add build testing

.github/workflows/build.yml

@@ -0,0 +1,20 @@
+name: Build
+on: [push, pull_request]
+
+jobs:
+  build:
+    name: "Build"
+    runs-on: ubuntu-latest
+    steps:
+      - name: Install additional build dependencies
+        run: sudo apt-get install -yqq llvm lld
+      - uses: actions/checkout@v4
+        with:
+          submodules: recursive
+      - name: Build
+        run: git clean -dxf && make -j$(nproc) CFLAGS_SRC="-Wall -Werror"
+      - name: Archive artifacts
+        uses: actions/upload-artifact@v4
+        with:
+          name: dtbloader
+          path: "build-*/dtbloader.*"