Option parsing in gnash is kind of broken atm.
In particular, we had a concept of Gui classes having
a chance to parse some commandline args (they get argc/argv)
and gtk gui actually passes argc/argv over to gtk libs.

But, we fail when we encounter an unknown option, so
it'll be impossible to pass anything down the line.

This blog post gives example of accepting unknown:
http://cxwangyi.blogspot.com/2010/06/boost-program-options-library.html

The remaining problem is that we can't register "positional"
parameters until all components had a chance to parse
the commanline, and drop what they parsed, or we won't be
able to tell what's a switch argument and what's a positional
parameter.