> So, since this patch allows python to be built 64-bit on a biarch
> system, and without it, the build doesn't work

This is simply not true. I can build Python 2.5 just fine for 64-bit
SPARC, using gcc, with

CC="gcc -m64" ./configure
make

Or, using SunPRO, with

CC="cc -m64" ./configure
make

I tested it myself, and it successfully builds a Python executable
(For gcc, the extension modules fail to load because it picks up
the wrong libgcc_s, which I believe is a gcc installation bug. For
SunPRO, the extension modules also build fine).

So before anything is fixed, I'd like to see an actual, reliable,
reproducable error report. The subject of this report (Python 2.5
64 bit compile fails on Solaris 10 with gcc) is not reproducable,
so I'm tempted to close this report as "works for me".