If you try to build Ruby 1.9.3 using rvm install ruby-1.9.3-p551, it will barf with compiler errors. The workaround, found here, is to use:

rvm install ruby-1.9.3-p551 --with-gcc=gcc

You will get a warning:

Ruby ‘ruby-1.9.3-p551’ was built using clang - but it’s not (fully) supported, expect errors.

However, I have run into any errors.

Yes, 1.9.3 is not supported and, in a perfect world, I would be able to upgrade projects using it.

No, I don’t care if you hate RVM.