fix: support nvcc and test (#2461)

* fix: support nvcc and test

* fixup! fix: support nvcc and test

* docs: mention what compilers fail

* fix: much simpler logic

* refactor: slightly faster / clearer

.github/workflows/ci.yml

@@ -289,6 +289,28 @@ jobs:
     - name: Interface test
       run: cmake --build build --target test_cmake_build
 
+  cuda:
+    runs-on: ubuntu-latest
+    name: "🐍 3.8 • CUDA 11 • Ubuntu 20.04"
+    container: nvidia/cuda:11.0-devel-ubuntu20.04
+
+    steps:
+    - uses: actions/checkout@v2
+
+    # tzdata will try to ask for the timezone, so set the DEBIAN_FRONTEND
+    - name: Install 🐍 3
+      run: apt-get update && DEBIAN_FRONTEND="noninteractive" apt-get install -y cmake python3-dev python3-pytest
+
+    - name: Configure
+      run: cmake -S . -B build -DPYBIND11_CUDA_TESTS=ON -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON
+
+    - name: Build
+      run: cmake --build build -j2 -v
+
+    - name: Python tests
+      run: cmake --build build --target pytest
+
+
   install-classic:
     name: "🐍 3.5 • Debian • x86 •  Install"
     runs-on: ubuntu-latest