Remove Regexp flags unsupported by JavaScript
Remove Regexp flags unsupported by JavaScript

And show a warning.
opal/opal,kachick/opal,Mogztter/opal,opal/opal,kachick/opal,kachick/opal,Mogztter/opal,opal/opal,Mogztter/opal,opal/opal,kachick/opal,Mogztter/opal