rational.hpp with gcc 3.0 prerelease

From: rwgk_at_[hidden]
Date: 2001-05-25 11:58:45

In order for rational.hpp to work with the latest gcc 3.0 CVS
snapshot (running under RedHat 6.1), I had to change line 494
of rational.hpp:

#if !(defined(__GNUC__) && __GNUC__ < 3) || defined __SGI_STL_PORT

Ralf