[PATCH] have cf_gen.cc use iostreams instead of stdio

Hi all,
   a bit frustrated by MinGW not easily offering some non-ansi calls,
I've ported cf_gen.cc to use iostreams instead of C stdio.
As the topic is a more general than mswin, I'd like to commit to trunk
instead of the branch.
Build-tested.

Thoughts?

-- 
    /kinkie