Timeline for dropping vs2017

[h-vetinari]

We bumped the default windows compilers across conda-forge to vs2019 over a year ago (https://github.com/conda-forge/conda-forge-pinning-feedstock/pull/3167), and usage of the previous vs2017 toolchain has dwindled.

Based on the following searches (in conda_build_config.yaml resp. meta.yaml), the only remaining feedstocks using vs2017 are as follows (I'm noting in brackets where the pin is set):

• [x] [meta] https://github.com/conda-forge/ace-feedstock/issues/54 (pinned from feedstock creation 3 years ago)
• [x] [CBC] https://github.com/conda-forge/cupy-feedstock/issues/250
• [x] [CBC] https://github.com/conda-forge/cudasirecon-feedstock/issues/28 (pin added only in June 2023)
• [x] [CBC] https://github.com/conda-forge/ensmallen-feedstock/issues/43 (pins set ~4 years ago)
• [x] [meta] https://github.com/conda-forge/example-robot-data-feedstock/issues/44 (pinned from feedstock creation 3 years ago)
• [ ] [CBC] https://github.com/conda-forge/fltk-feedstock/issues/25 (pin added only in July 2023)
• [x] [meta] https://github.com/conda-forge/igraph-feedstock/issues/65 (pins set ~4 years ago)
• [x] [meta] https://github.com/conda-forge/libignition-physics-feedstock (false positive, appears in patch name)
• [x] [meta] https://github.com/conda-forge/louvain-feedstock/issues/30 (pins set 3 years ago)
• [x] [meta] https://github.com/conda-forge/lua-feedstock/issues/50 (pins set 4 years ago)
• [x] [meta] https://github.com/conda-forge/panda3d-feedstock/issues/45 (pins set 3 years ago)
• [x] [meta] https://github.com/conda-forge/proxsuite-feedstock/issues/53
• [x] [meta] https://github.com/conda-forge/pycppad-feedstock/issues/19 (pins set 2 years ago)
• [x] [meta] https://github.com/conda-forge/pyinterp-feedstock/issues/97 (pinned from feedstock creation 4 years ago)
• [x] [meta] https://github.com/conda-forge/sdl_image-feedstock/issues/9 (feedstock for old version; sdl2_image uses regular setup)
• [x] [CBC] https://github.com/conda-forge/sox-feedstock/issues/31 (pins set 2 years ago)
• [x] [CBC] https://github.com/conda-forge/vigra-feedstock/issues/128

In particular, everything that added pins on vs2017 before August 2022 was "just" selecting the default compilers.

Comatose / dead feedstocks

• [meta] https://github.com/conda-forge/azure-iot-sdk-c-feedstock
• [meta] https://github.com/conda-forge/azure-uamqp-c-feedstock
• [meta] https://github.com/conda-forge/azure-uhttp-c-feedstock
• [meta] https://github.com/conda-forge/azure-umqtt-c-feedstock
• [meta] https://github.com/conda-forge/libxfoil-feedstock
• [meta] https://github.com/conda-forge/oclgrind-feedstock
• [meta] https://github.com/conda-forge/parson-feedstock
• [meta] https://github.com/conda-forge/pytide-feedstock
• [CBC] https://github.com/conda-forge/sciplot-feedstock
• [meta] https://github.com/conda-forge/soem-feedstock

[h-vetinari]

Apparently MSFT removed the vc141 components (see #78), so I think this might have been decided for us.