Building GCC 4.9 biarch (i686+x86_64) on Debian 6.0 i686

[Alex Blekhman]

Andrew Haley <aph <at> redhat.com> writes:
> Cross-compiling from 32- to 64-bit hosts is notoriously tricky.  People
> almost always go in the opposite direction.  I don't even know if it
> can be done.

I can live with 64-bit system, which has 64-bit GCC. What is essential for 
me is that I can build both 32-bit and 64-bit targets and then run 32-bit 
targets (during test phase of the build).

How difficult (easy?) is it to have 64-bit Debian/Redhat machine running 
32-bit executables?

Thanks
Alex