As of Ruby 3.1, the Ruby Windows Installer is now releasing its platform as x64-mingw-ucrt. Refer to ruby/setup-ruby#193

Compare Ruby 3.0 vs. 3.1 on Windows:

ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x64-mingw32]
ruby 3.1.1p18 (2022-02-18 revision 53f5fc4236) [x64-mingw-ucrt]

Currently, when running gem install grpc on Ruby 3.1 x64-mingw-ucrt, gem fails to recognize the platform, it attempts to do a native build. I'd like to request that grpc support the x64-mingw-ucrt platform.

As a reference, Nokogiri is providing an x64-mingw-ucrt build. (Note that they aren't providing an x86 flavor, which is fine I guess.) https://rubygems.org/gems/nokogiri/versions/1.13.6-x64-mingw-ucrt