opal/opal — pull request #363 by rubys (2013-09-12 13:47:51+00:00)
Title: untaint corelib, stdlib, and "safe" requires

I'm trying to run opal in a [safe](http://www.ruby-doc.org/docs/ProgrammingRuby/html/taint.html) environment, and this is the first problem I ran into. If I run into more, I'll provide more patches. These changes will not affect anybody who runs code in a normal ("unsafe") environment.