Quick post for future me:
Jekyll was being incredibly painful on MacOS this morning.
Installing eventmachine 1.2.7 with native extensions Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
Could not find concurrent-ruby-1.1.7 in any of the sources Run `bundle install` to install missing gems.
listen-3.2.1 requires ruby version >= 2.2.7, ~> 2.2, which is incompatible with the current version, ruby 3.0.0p0
The fix was surprisingly simple:
Which looked good but the bundle exec jekyll serve still crashed with:
cannot load such file -- webrick (LoadError)
so we add:
bundle add webrick
and then the bundle exec jekyll serve is back on track.