Version 5.3 Release Candidate 2

Thank you to everyone who reported bugs (or successes) in RC1.  There
have been quite a few fixes as a result and now everything that I'm
aware of has been fixed.  I have upped the version string to RC2 so this
is the last chance to check that everything is working before the release.

I've made new versions of the pre-built compilers in the imports 
directory and moved the version 5.3-specific basis library files into 
their normal locations.  This means that it's sufficient to run
./configure
make
and it isn't necessary to run the "make compiler" step.

If I don't hear anything in the next week or so I'll release 5.3.

Regards,
David