Compiling 5.10.1 as 32/64 bit fat binary on 10.6.1

(Note to moderators: sorry if this is the 3d time you have gotten this (or a
similar) post from me, I have tried twice through Google Groups and gotten
no response/post, so fear it may be lost).

I am trying to compile 5.10.1 on OS X 10.6.1.  I would like to create a
Œfat¹ binary containing binaries for both the 64-bit x86_64 and 32-bit i386
architectures.  This is the way the system install of 5.10.0 appears to have
been compiled.  However, I cannot seem to get the right combination of
compiler flags and config options, even when copying most of them from the
system default perl.  Has anyone succeeded in compiling a 32/64 fat binary
of 5.10.1, and could you share your config.sh file (or at least the relevant
magic)?

Thanks in advance
Tobias Zimmerman