ghc 6.0.1 and Mac OS X 10.2.6 build

[Alastair Reid]

> I assumed that the nlist test would still be sufficient for other
> platforms, as it also correctly determined that Mac OS X itself uses
> symbols with underscores *everywhere* else.

I'm afraid not.
At least one of the BSDs has problems with it.  (At least, it kept getting the 
answer wrong for Hugs until we switched to testing what dlsym does instead of 
testing what nlist does.)

--
Alastair Reid