|Ask perl if a given scalar looks like a number (requires Inline::C).
Inspired by Slaven Rezic's "Include Perl_looks_like_number in Scalar::Util?" post to p5p.
Hopefully this function, or something very similar to it, should be making it into Scalar::Util per the p5p thread.
update: changed the title (was Is it a number?) as it was a little ambiguous in relation to the code