Added CI build skeleton

.github/workflows/CI-build.yml

@@ -0,0 +1,53 @@
+# This is a basic workflow to help you get started with Actions
+
+name: threadx_build_cortex_m4
+
+# Controls when the action will run. Triggers the workflow on push or pull request
+# events but only for the master branch
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+# A workflow run is made up of one or more jobs that can run sequentially or in parallel
+jobs:
+  # This workflow contains a single job called "build"
+  build:
+    # The type of runner that the job will run on
+    runs-on: ubuntu-latest
+
+    # Steps represent a sequence of tasks that will be executed as part of the job
+    steps:
+    # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
+    - name: Checkout sources recursively
+      uses: actions/checkout@v2
+      with:
+        token: ${{ secrets.REPO_SCOPED_TOKEN }}
+        submodules: true
+
+#     - name: Install build-essential
+#       run: sudo apt-get install build-essential
+
+    # Get the arm-non-eabi-gcc toolchain   
+    - name: Install arm-none-eabi-gcc
+      uses: fiam/arm-none-eabi-gcc@v1
+      with:
+          release: '9-2019-q4' # The arm-none-eabi-gcc release to use.
+
+    # Get CMake into the environment
+    - name: Install cmake 3.17.1
+      uses: lukka/get-cmake@v3.17.1
+
+    # Get Ninja into the environment
+    - name: Install ninja-build
+      uses: seanmiddleditch/gha-setup-ninja@v1
+
+    # Prepare the build system
+    - name: Prepare build system
+      run: cmake -Bbuild -DCMAKE_TOOLCHAIN_FILE=./cmake/cortex_m4.cmake -GNinja .
+
+    - name: Compile and link
+      run: cmake --build ./build
+
+