RUBYOPT=--enable=frozen-string-literal

[MSP-Greg]

I was working with RubyGems testing, and added --enable=frozen-string-literal to RUBYOPT.

There were a few errors, all seemed to be due to RDoc. I then ran the test-all rdoc tests with the setting, and there were also errors.

I just thought I'd point it out, as I couldn't find mention of it in existing issues. I also realize this is a 'sometime in the future we'll care about that' item...