How to cross compile custom kernel?

[David Wolinski]

I have a fast x86_64 machine and a slow x86 machine.  I'd like to use
the fast x86_64 machine to build a custom kernel for the x86 machine.

On the x86_64 machine:

  -  In the kernel build tree, I copy configs/kernel-XXX-i686.config to
my working .config file since I want the kernel built for that
architecture
  -  "make gconfig" to customize some kernel options
  -  But while configuring I notice that all of the architecture options
have been set to x86_64 choices (and x86 choices are unavailable)

Clearly "make gconfig" has adjusted the original .config options to suit
my build machine's x86_64 architecture.

I still want to use "make gconfig" to customize kernel options, but how
can I prevent it from changing the architecture automatically?

Thanks for any help.