[plt-scheme] cross-compilation porting question

Hi,

I'm a scheme newbie. Since a linksys nslu2 (xscale CPU, see
http://nslu2-linux.org) is my only constant-on linux machine, I'm
trying to port mzscheme over by cross compilation. The porting went
pretty well and I actually get the mzscheme binary working. Those who
are interested can take a look at the work-in-progress
http://cvs.sourceforge.net/viewcvs.py/nslu/unslung/make/mzscheme.mk.

The problem is that collects contain some native extensions. On cross
build host, when I do the install step, I can use the host mzscheme to
generate all zo's fine, but it insisted on using the build machine's
gcc to build the target .so's - apparently that would fail. Is there a
way to

1. disable native .so extension?
2. or even better, have mzscheme use the target_cc for compiling
native extensions?

I know probably I can make native compilation working, but
cross-compilation is really preferred. Native compilation is so slow.

Thanks for any help,

-Brian Zhou