Add github actions

Author: liamfraser

.github/workflows/cmake.yml

@@ -0,0 +1,59 @@
+name: CMake
+on: [push]
+
+env:
+  # Customize the CMake build type here (Release, Debug, RelWithDebInfo, etc.)
+  BUILD_TYPE: Release
+
+jobs:
+  build:
+    runs-on: [self-hosted, Linux, X64]
+
+    steps:
+    - name: Clean workspace
+      run: |
+        echo "Cleaning up previous run"
+        rm -rf "${{ github.workspace }}"
+        mkdir -p "${{ github.workspace }}"
+
+    - name: Checkout pico-examples
+      uses: actions/checkout@v2
+      with:
+        path: pico-examples
+
+    - name: Checkout pico-sdk/develop
+      uses: actions/checkout@v2
+      with:
+        repository: raspberrypi/pico-sdk
+        ref: develop
+        path: pico-sdk
+
+    - name: Checkout pico-sdk submodules
+      working-directory: ${{github.workspace}}/pico-sdk
+      run: git submodule update --init
+
+    - name: Create Build Environment
+      # Some projects don't allow in-source building, so create a separate build directory
+      # We'll use this as our working directory for all subsequent commands
+      working-directory: ${{github.workspace}}/pico-examples
+      run:  cmake -E make_directory ${{github.workspace}}/pico-examples/build
+
+    - name: Configure CMake
+      # Use a bash shell so we can use the same syntax for environment variable
+      # access regardless of the host operating system
+      shell: bash
+      working-directory: ${{github.workspace}}/pico-examples/build
+      # Note the current convention is to use the -S and -B options here to specify source 
+      # and build directories, but this is only available with CMake 3.13 and higher.  
+      # The CMake binaries on the Github Actions machines are (as of this writing) 3.12
+      run: PICO_SDK_PATH=../../pico-sdk cmake .. -DCMAKE_BUILD_TYPE=$BUILD_TYPE
+
+    - name: Get core count
+      id: core_count
+      run : cat /proc/cpuinfo  | grep processor | wc -l
+
+    - name: Build
+      working-directory: ${{github.workspace}}/pico-examples/build
+      shell: bash
+      # Execute the build.  You can specify a specific target with "--target <NAME>"
+      run: cmake --build . --config $BUILD_TYPE --parallel ${{steps.core_count.outputs.output}}