Add Github Actions CI builds and releases

The new Github Actions offers similar functionality as the Travis CI
integration, but with some interesting extra features:

The build action is almost equivalent to the existing Travis build
configuration. But as an extra feature, the build artifacts are now
available for download.

The release action does automatically build a distribution tarball and
create a Github release, whenever a new version is tagged and pushed.

.github/workflows/build.yml

@@ -0,0 +1,95 @@
+name: Build
+
+on: [push, pull_request]
+
+jobs:
+
+  linux:
+
+    name: Linux
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        compiler: [gcc, clang]
+
+    env:
+      CC: ${{ matrix.compiler }}
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install dependencies
+        run: sudo apt-get install libbluetooth-dev libusb-1.0-0-dev
+      - run: autoreconf --install --force
+      - run: ./configure --prefix=/usr
+      - run: make
+      - run: make distcheck
+      - name: Package artifacts
+        run: |
+          make install DESTDIR=$PWD/artifacts
+          tar -czf ${{ github.job }}-${{ matrix.compiler }}.tar.gz -C artifacts usr
+      - uses: actions/upload-artifact@v2
+        with:
+          name: ${{ github.job }}-${{ matrix.compiler }}
+          path: ${{ github.job }}-${{ matrix.compiler }}.tar.gz
+
+  mac:
+
+    name: Mac
+
+    runs-on: macos-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        compiler: [gcc, clang]
+
+    env:
+      CC: ${{ matrix.compiler }}
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install dependencies
+        run: brew install autoconf automake libtool hidapi libusb
+      - run: autoreconf --install --force
+      - run: ./configure --prefix=/usr
+      - run: make
+      - run: make distcheck
+      - name: Package artifacts
+        run: |
+          make install DESTDIR=$PWD/artifacts
+          tar -czf ${{ github.job }}-${{ matrix.compiler }}.tar.gz -C artifacts usr
+      - uses: actions/upload-artifact@v2
+        with:
+          name: ${{ github.job }}-${{ matrix.compiler }}
+          path: ${{ github.job }}-${{ matrix.compiler }}.tar.gz
+
+  windows:
+
+    name: Windows
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        arch: [i686, x86_64]
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install dependencies
+        run: sudo apt-get install gcc-mingw-w64 binutils-mingw-w64 mingw-w64-tools
+      - run: autoreconf --install --force
+      - run: ./configure --host=${{ matrix.arch }}-w64-mingw32 --prefix=/usr
+      - run: make
+      - run: make distcheck
+      - name: Package artifacts
+        run: |
+          make install DESTDIR=$PWD/artifacts
+          tar -czf ${{ github.job }}-${{ matrix.arch }}.tar.gz -C artifacts usr
+      - uses: actions/upload-artifact@v2
+        with:
+          name: ${{ github.job }}-${{ matrix.arch }}
+          path: ${{ github.job }}-${{ matrix.arch }}.tar.gz

.github/workflows/release.yml

@@ -0,0 +1,61 @@
+name: Release
+
+on:
+  push:
+    tags: 'v*'
+
+jobs:
+  release:
+    name: Release
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Version number
+        id: version
+        run: |
+          VERSION="${GITHUB_REF/refs\/tags\/v/}"
+          if [ "${VERSION}" = "${VERSION%%-*}" ]; then
+             PRERELEASE=false
+          else
+             PRERELEASE=true
+          fi
+          echo ::set-output name=version::${VERSION}
+          echo ::set-output name=prerelease::${PRERELEASE}
+
+      - name: Build distribution tarball
+        id: build
+        run: |
+          sudo apt-get install libbluetooth-dev libusb-1.0-0-dev
+          autoreconf --install --force
+          ./configure
+          make
+          make distcheck
+
+      - name: Check tarball version number
+        id: check
+        run: |
+          FILENAME="libdivecomputer-${{ steps.version.outputs.version }}.tar.gz"
+          if [ ! -f "${FILENAME}" ]; then
+             echo ::error ::Tarball \'${FILENAME}\' not found!
+             exit 1
+          fi
+
+      - uses: actions/create-release@v1
+        id: release
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          tag_name: ${{ github.ref }}
+          release_name: ${{ github.ref }}
+          prerelease: ${{ steps.version.outputs.prerelease }}
+
+      - uses: actions/upload-release-asset@v1
+        id: upload
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.release.outputs.upload_url }}
+          asset_path: libdivecomputer-${{ steps.version.outputs.version }}.tar.gz
+          asset_name: libdivecomputer-${{ steps.version.outputs.version }}.tar.gz
+          asset_content_type: application/gzip