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.github/workflows/build.yml

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+name: Build
+on:
+  - push
+  - pull_request
+
+jobs:
+  natives-linux-windows:
+    name: Linux (x86/ARM/PPC) and Windows native library compilation
+    runs-on: ubuntu-18.04
+
+    defaults:
+      run:
+        working-directory: src/main/c
+
+    steps:
+      - name: Checkout the code
+        uses: actions/checkout@v2
+      - name: Setup Java
+        uses: actions/setup-java@v1
+        with:
+          java-version: 8
+      - name: Install build prerequisites
+        run: |
+          sudo apt update
+          sudo make crosstools
+
+      - name: Build the Linux and Windows native libraries
+        run: |
+          make clean-linux clean-windows
+          make linux windows
+
+      # The names of the artifacts containing native libraries correspond
+      # exactly to the directories inside `src/main/c/resources/native`. That
+      # way, the Java build job can pull down all artifacts and unpack them
+      # into that directory to overwrite the versions in-repo. This is sadly
+      # necessary because the actions/download-artifact@v2 action flattens
+      # paths inside artifacts. If it retained full relative paths, we could
+      # put Linux and Windows natives inside the same artifact, and we could be
+      # flexible with the artifact names. But it doesn't, so we can't, and we
+      # can't.
+      - name: Upload Linux native libraries
+        uses: actions/upload-artifact@v2
+        with:
+          name: linux
+          path: src/main/c/resources/native/linux
+      - name: Upload Windows native libraries
+        uses: actions/upload-artifact@v2
+        with:
+          name: windows
+          path: src/main/c/resources/native/windows
+
+  natives-macos:
+    name: macOS native library compilation
+    runs-on: macos-10.15
+
+    defaults:
+      run:
+        working-directory: src/main/c
+
+    steps:
+      - name: Checkout the code
+        uses: actions/checkout@v2
+      - name: Setup Java
+        uses: actions/setup-java@v1
+        with:
+          java-version: 8
+
+      - name: Build the macOS native libraries
+        run: |
+          make clean-osx
+          make osx
+
+      - name: Upload macOS native libraries
+        uses: actions/upload-artifact@v2
+        with:
+          name: osx
+          path: src/main/c/resources/native/osx/libNRJavaSerial.jnilib
+
+  natives-freebsd:
+    name: FreeBSD native library compilation
+    runs-on: ubuntu-18.04
+    container:
+      image: empterdose/freebsd-cross-build:9.3
+      env:
+        JAVA_HOME: /usr/lib/jvm/default-jvm
+
+    defaults:
+      run:
+        working-directory: src/main/c
+
+    steps:
+      - name: Checkout the code
+        uses: actions/checkout@v2
+      - name: Setup Java
+        # This feels extremely dirty, but the only native header we care about
+        # is `jni_md.h`, and it is exactly identical between Linux and FreeBSD
+        # (at least in OpenJDK 8).
+        run: |
+          apk add openjdk8
+          ln -s $JAVA_HOME/include/linux $JAVA_HOME/include/freebsd
+
+      - name: Build the FreeBSD native libraries
+        run: |
+          make clean-freebsd
+          settarget i386-freebsd9 make freebsd32
+          settarget x86_64-freebsd9 make freebsd64
+
+      - name: Upload FreeBSD native libraries
+        uses: actions/upload-artifact@v2
+        with:
+          name: freebsd
+          path: src/main/c/resources/native/freebsd
+
+  java:
+    name: Java compilation
+    runs-on: ubuntu-18.04
+
+    needs:
+      - natives-linux-windows
+      - natives-macos
+      - natives-freebsd
+
+    steps:
+      - name: Checkout the code
+        uses: actions/checkout@v2
+      - name: Setup Java
+        uses: actions/setup-java@v1
+        with:
+          java-version: 8
+
+      - name: Download native libraries
+        uses: actions/download-artifact@v2
+        with:
+          path: src/main/c/resources/native
+
+      - name: Build the Java library
+        run: ./gradlew build
+
+      - name: Determine commit hash for artifact filename
+        id: vars
+        run: echo "::set-output name=short-rev::$(git rev-parse --short HEAD)"
+      - name: Upload build artifacts
+        uses: actions/upload-artifact@v2
+        with:
+          name: nrjavaserial-${{steps.vars.outputs.short-rev}}
+          path: build/libs/*.jar