Add build action to build libmongoc system libraries

Author: alcaeus

.github/actions/linux/build-libmongoc/action.yml

@@ -0,0 +1,54 @@
+name: "Build libmongoc"
+description: "Builds and install libmongoc"
+inputs:
+  prefix:
+    description: "Prefix to install libmongoc to"
+    default: "/usr/local"
+  version:
+    description: "Libmongoc version to build"
+    required: true
+runs:
+  using: composite
+
+  steps:
+    - name: Download libmongoc
+      shell: bash
+      working-directory: /tmp
+      run: wget "https://github.com/mongodb/mongo-c-driver/archive/refs/tags/${LIBMONGOC_VERSION}.tar.gz" --output-document="mongo-c-driver.tar.gz"
+      env:
+        LIBMONGOC_VERSION: ${{ inputs.version }}
+
+    - name: Extract libmongoc
+      shell: bash
+      working-directory: /tmp
+      run: tar xf "mongo-c-driver.tar.gz"
+
+    - name: Configure cmake
+      shell: bash
+      working-directory: /tmp
+      run: |
+        cmake \
+          -S "mongo-c-driver-${LIBMONGOC_VERSION}" \
+          -B _build \
+          -D CMAKE_BUILD_TYPE=RelWithDebInfo \
+          -D BUILD_VERSION="${LIBMONGOC_VERSION}" \
+          -D ENABLE_MONGOC=ON \
+          -D ENABLE_TRACING=ON
+      env:
+        LIBMONGOC_VERSION: ${{ inputs.version }}
+
+    - name: Build libmongoc
+      shell: bash
+      working-directory: /tmp
+      run: cmake --build _build --config RelWithDebInfo --parallel
+
+    - name: Install libmongoc
+      shell: bash
+      working-directory: /tmp
+      run: sudo cmake --install _build --prefix "${PREFIX}" --config RelWithDebInfo
+      env:
+        PREFIX: ${{ inputs.prefix }}
+
+    - name: Check pkg-config availability
+      shell: bash
+      run: pkg-config --modversion mongoc2

.github/workflows/system-libs.yml

@@ -0,0 +1,23 @@
+name: "System library tests"
+
+on:
+  push:
+    branches:
+      - "build-system-libs"
+
+jobs:
+  tests:
+    name: "Build"
+    runs-on: "ubuntu-24.04"
+
+    steps:
+      - name: "Checkout"
+        uses: "actions/checkout@v4"
+        with:
+          submodules: true
+
+      - name: "Build libmongoc"
+        id: build-libmongoc
+        uses: ./.github/actions/linux/build-libmongoc
+        with:
+          version: 2.0.1