Issues serving Jekyll to localhost, eventmachine 1.2.7 has an error when installing

Question

Not sure what to do to specifically fix this problem, googled and nothing solved my question. When I try to:

bundle exec jekyll serve

I get told:

Could not find eventmachine-1.2.7 in any of the sources
Run `bundle install` to install missing gems.

Then I:

bundle install

Only to get this:

Installing eventmachine 1.2.7 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    current directory: /private/var/folders/7f/2c2swwc1153899dmr8781_x40000gn/T/bundler20201130-34411-1lzt2fceventmachine-1.2.7/gems/eventmachine-1.2.7/ext
/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/bin/ruby -I /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0 -r
./siteconf20201130-34411-pd54nh.rb extconf.rb
mkmf.rb can't find header files for ruby at /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/include/ruby.h

You might have to install separate package for the ruby development
environment, ruby-dev or ruby-devel for example.

extconf failed, exit code 1

Gem files will remain installed in /var/folders/7f/2c2swwc1153899dmr8781_x40000gn/T/bundler20201130-34411-1lzt2fceventmachine-1.2.7/gems/eventmachine-1.2.7 for
inspection.
Results logged to
/var/folders/7f/2c2swwc1153899dmr8781_x40000gn/T/bundler20201130-34411-1lzt2fceventmachine-1.2.7/extensions/universal-darwin-20/2.6.0/eventmachine-1.2.7/gem_make.out

An error occurred while installing eventmachine (1.2.7), and Bundler cannot continue.
Make sure that `gem install eventmachine -v '1.2.7' --source 'https://rubygems.org/'` succeeds before bundling.

In Gemfile:
  minima was resolved to 2.5.1, which depends on
    jekyll-feed was resolved to 0.13.0, which depends on
      jekyll was resolved to 4.0.0, which depends on
        em-websocket was resolved to 0.5.1, which depends on
          eventmachine

Where am I going wrong here? Just updated to macOS 11.0.1, this is my first time trying to serve jekyll since the update. Thanks y'all!

Answer 1

Just try:

gem install eventmachine -v '1.2.7' -- --with-cppflags=-I/usr/local/opt/openssl/include