Add CI workflows for Linux, MacOS and Windows.

This is equivalent to the CI workflows added to the yquake2 main
repository. The workflows are triggered on commit, for new pull
requests and when the pull request branch is updated. The CI is
mostly for providing users with up to date test builds.

.github/workflows/linux.yml

@@ -0,0 +1,46 @@
+name: Testbuild for Linux
+run-name: testbuild_linux
+on:
+  push:
+    branches:
+      - 'master'
+  pull_request:
+    types:
+      - edited
+      - opened
+      - synchronize
+concurrency:
+  # Cancel concurrent workflows for the same PR or commit hash.
+  group: ${{github.workflow}}-${{github.event_name == 'pull_request' && github.head_ref || github.sha}}
+  cancel-in-progress: true
+jobs:
+  build_ubuntu_x64_64:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - env: ubuntu
+    steps:
+    - name: Check out repository code
+      uses: actions/checkout@v4
+    - name: Build
+      run: |
+        # Public runners come with 2 CPUs.
+        make -j2
+    - name: Create testbuild package
+      run: |
+        # Create release directory tree
+        mkdir -p publish/quake2-xatrix-linux-${{github.sha}}/misc/docs
+        # Copy release assets
+        cp -r release/* publish/quake2-xatrix-linux-${{github.sha}}/
+        # Copy misc assets
+        cp -r stuff/mapfixes publish/quake2-xatrix-linux-${{github.sha}}/misc
+        cp LICENSE publish/quake2-xatrix-linux-${{github.sha}}/misc/docs/LICENSE.txt
+        cp README.md publish/quake2-xatrix-linux-${{github.sha}}/misc/docs/README.txt
+    - name: Upload testbuild package
+      uses: actions/upload-artifact@v4
+      with:
+        name: quake2-xatrix-linux-${{github.sha}}
+        path: publish/
+        if-no-files-found: error

.github/workflows/macos.yml

@@ -0,0 +1,51 @@
+name: Testbuild for MacOS
+run-name: testbuild_macos
+on:
+  push:
+    branches:
+      - 'master'
+  pull_request:
+    types:
+      - edited
+      - opened
+      - synchronize
+concurrency:
+  # Cancel concurrent workflows for the same PR or commit hash.
+  group: ${{github.workflow}}-${{github.event_name == 'pull_request' && github.head_ref || github.sha}}
+  cancel-in-progress: true
+jobs:
+  build_macos_aarch64:
+    runs-on: macos-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - env: macos
+    steps:
+    - name: Install build dependencies
+      run: |
+        brew update
+        brew install make
+        brew upgrade
+    - name: Check out repository code
+      uses: actions/checkout@v4
+    - name: Build
+      run: |
+        # Public runners come with 3 CPUs.
+        gmake -j3
+    - name: Create testbuild package
+      run: |
+        # Create release directory tree
+        mkdir -p publish/quake2-xatrix-macos-${{github.sha}}/misc/docs
+        # Copy release assets
+        cp -r release/* publish/quake2-xatrix-macos-${{github.sha}}/
+        # Copy misc assets
+        cp -r stuff/mapfixes publish/quake2-xatrix-macos-${{github.sha}}/misc
+        cp LICENSE publish/quake2-xatrix-macos-${{github.sha}}/misc/docs/LICENSE.txt
+        cp README.md publish/quake2-xatrix-macos-${{github.sha}}/misc/docs/README.txt
+    - name: Upload testbuild package
+      uses: actions/upload-artifact@v4
+      with:
+        name: quake2-xatrix-macos-${{github.sha}}
+        path: publish/
+        if-no-files-found: error

.github/workflows/win32.yml

@@ -0,0 +1,57 @@
+name: Testbuild for Win32
+run-name: testbuild_win32
+on:
+  push:
+    branches:
+      - 'master'
+  pull_request:
+    types:
+      - edited
+      - opened
+      - synchronize
+concurrency:
+  # Cancel concurrent workflows for the same PR or commit hash.
+  group: ${{github.workflow}}-${{github.event_name == 'pull_request' && github.head_ref || github.sha}}
+  cancel-in-progress: true
+jobs:
+  build_mingw_x86_32:
+    runs-on: windows-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - { sys: mingw32, env: i686 }
+    steps:
+    - uses: msys2/setup-msys2@v2
+      with:
+        msystem: ${{matrix.sys}}
+        update: true
+        install: >-
+          git
+          make
+          mingw-w64-${{matrix.env}}-gcc
+          mingw-w64-${{matrix.env}}-make
+    - name: Check out repository code
+      uses: actions/checkout@v4
+    - name: Build
+      shell: msys2 {0}
+      run: |
+        # Public runners come with 2 CPUs.
+        make -j2
+    - name: Create testbuild package
+      shell: msys2 {0}
+      run: |
+        # Create release directory tree
+        mkdir -p publish/quake2-xatrix-win32-${{github.sha}}/misc/docs
+        # Copy release assets
+        cp -r release/* publish/quake2-xatrix-win32-${{github.sha}}/
+        # Copy misc assets
+        cp -r stuff/mapfixes publish/quake2-xatrix-win32-${{github.sha}}/misc
+        cp LICENSE publish/quake2-xatrix-win32-${{github.sha}}/misc/docs/LICENSE.txt
+        cp README.md publish/quake2-xatrix-win32-${{github.sha}}/misc/docs/README.txt
+    - name: Upload testbuild package
+      uses: actions/upload-artifact@v4
+      with:
+        name: quake2-xatrix-win32-${{github.sha}}
+        path: publish/
+        if-no-files-found: error