Support risc-v (#287)

Co-authored-by: DaniAffCH <danieleaffinita2000@gmail.com>
Co-authored-by: Corentin Le Molgat <corentinl@google.com>

.github/workflows/riscv_linux_cmake.yml

@@ -0,0 +1,28 @@
+name: RISCV Linux CMake
+
+on:
+  push:
+  pull_request:
+  schedule:
+    # min hours day(month) month day(week)
+    - cron: '0 0 7,22 * *'
+
+jobs:
+  # Building using the github runner environement directly.
+  make:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        targets: [
+          [riscv32],
+          [riscv64],
+        ]
+      fail-fast: false
+    env:
+      TARGET: ${{ matrix.targets[0] }}
+    steps:
+    - uses: actions/checkout@v2
+    - name: Build
+      run: make --directory=cmake/ci ${TARGET}_build
+    - name: Test
+      run: make --directory=cmake/ci ${TARGET}_test