hardcoding -m32/-m64 is more harmful than using the toolchain defaults

[Martin Buchholz]

I agree that configure should try to invoke "the compiler" without any
flags by default, but make it easy for users to supply them.  If some
platform like SLES 10 on Linux/ppc64 wants to build 32-bit binaries, assume
that this is intended and let it go ahead!  Don't just assume the distro
maintainers are wrong.  I have some sympathy for the idea that "32-bit
ought to be enough for everybody", and if it's not, switch to 64-bit then.
The main reason to build everything 64-bit is simple avoidance of confusion
and replication of runtime environments.