64-bit ports to Solaris.

[Dr. David Kirkby]

There's quite a few bug fixes been merged into 4.5.3.alpha0, which should
greatly aid Sage building on

* Solaris 10 x86 (64-bit)
* Solaris 10 SPARC (64-bit)
* OpenSolaris x64 (64-bit).

Unless there are a number of packages reviewed and committed soon, I don't see
it being possible to just build Sage 64-bit on these Solaris systems, but I
think it will be quite close. It might be feasible to bet 4.5.3 building 64-bit
without patches, but I suspect it will be possible the release after that.

I've asked William if we really need sympow, as that is presenting a problem and
the code looks far from clean. I believe it is very specialised and has limited
use. William might consider just removing it from Sage.

Dave