Missing symbols from libraries on Mac OS X builds: Addendum

Hi again,

Looks like TH was trying to link against some code produced by an 
earlier version of GHC HEAD (still 6.3 though) and that is why the 
symbol referencing error occurred. So perhaps there is no _need_ for 
this symbol anymore, although it still seems to exist on Linux builds.

Any ideas why it's no longer being generated?

Sean