Compile ruby - 'i386/eflags.h' file not found

Anyone have experience installing ruby on their Mac with chruby? Tried to help a friend set up Jekyll but she ran into this error when trying to install ruby-install ruby:

compile ruby - 'i386/eflags.h' file not found

Environment:

  • MacOS Monterry Intel Chip
  • bash
  • ?? What other info should I give

This looks similar: macos - gem install - fatal error: 'ruby/config.h' file not found in Mojave - Stack Overflow, so I followed the advice there to try and install through rubyenv, but the same thing happened.

Things yet to try: