macOS_SDK_headers_for_macOS_10.14.pkg doesn't exist on my system I am trying to install gem packages.

I am missing the macOS_SDK_headers_for_macOS_10.14.pkg file from /Library/Developer/CommandLineTools/Packages/. I found the link to download the .pkg, but I need an Apple Developer account, which costs $100 a year. 

Is there anywhere on my system besides /Library/Developer/CommandLineTools/Packages/ that this file can be found? If not, is there a source where I don't have to pay $100? I just want to install a gem! I did try to use the locate command by the way.
Please consider using Homebrew to install rbenv instead of using system Ruby. Then configure it to your liking and get the gems you need. Please see this Homebrew, Ruby, and Gems article for details.



To install Homebrew, if you have not yet, or if you had trouble with it, please follow this Install homebrew on MacOS Mojave  article or find a similar for your version of MACOS. The important thing is to agree to Command Line Tools License Agreement that may popup (or stay hidden?) in the middle of the install, and may prevent you from finishing the install.