ci: Add GitHub CI

.github/workflows/build.yaml

@@ -0,0 +1,91 @@
+name: Build
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  build-linux:
+    name: "Linux"
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Checkout source code
+        uses: actions/checkout@v4
+        with:
+          submodules: true
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.13'
+
+      - name: Install deps
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y \
+            libfftw3-dev \
+            libpng-dev \
+            gcc-14 \
+            g++-14
+
+      - name: Use GCC 14 to avoid a bug in tests with old gcc - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79700
+        run: |
+          echo "CC=gcc-14"  >> $GITHUB_ENV
+          echo "CXX=g++-14" >> $GITHUB_ENV
+
+      - name: Install NumPy
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install --only-binary=:all: numpy
+
+      - name: Run tests
+        run: make testall
+
+  build-windows:
+    name: "Windows (MSVC)"
+    runs-on: windows-2022
+
+    steps:
+      - name: Checkout source code
+        uses: actions/checkout@v4
+        with:
+          submodules: true
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.13'
+
+      - name: Install NumPy
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install --only-binary=:all: numpy
+
+      - name: Set up MSVC dev command prompt (x64)
+        uses: ilammy/msvc-dev-cmd@v1
+        with:
+          arch: x64
+
+      - name: Install C/C++ deps via vcpkg
+        run: |
+          C:\vcpkg\vcpkg.exe install fftw3:x64-windows libpng:x64-windows
+
+      - name: Install pkg-config
+        run: choco install -y pkgconfiglite
+
+      - name: Configure (CMake, MSVC)
+        run: >
+          cmake -S . -B build
+          -G "Visual Studio 17 2022"
+          -A x64
+          -DCMAKE_TOOLCHAIN_FILE=C:\vcpkg\scripts\buildsystems\vcpkg.cmake
+          -DCMAKE_BUILD_TYPE=Release
+          -DKISSFFT_TEST=OFF
+          -DKISSFFT_TOOLS=OFF
+
+      - name: Build
+        run: cmake --build build --config Release --parallel
+
+      #- name: Test
+      #  working-directory: build
+      #  run: ctest -C Release --output-on-failure