message: see the comment in the change for context
diff: @@ -161,9 +161,13 @@ jobs:
  os: windows-2016
  compiler: gcc
  + # this one fails like this: https://github.com/onqtam/doctest/runs/683076654
  + # #error Despite the presence of some Clang-related bits, this header currently does not support Clang.
  + # perhaps _SILENCE_CLANG_CONCEPTS_MESSAGE could be used, as indicated in the error message...
  - name: windows-2019-clang-cl
  os: windows-2019
  compiler: clang-cl
  + continue-on-error: true
  - name: windows-2019-clang
  os: windows-2019
  