build using shipped kernel config fails

[Robert P. J. Day]

  as an attempt at some debugging, i decided to start from
scratch and build a kernel using the shipped source tree,
and based on the config file found in /boot.  theoretically,
if this worked, this should produce the same kernel and
modules that are installed originally.  at least that's what
one would assume.

  however, using that kernel source tree and config file 
(and gcc32) produced a compile error on the aic7xxx_osm module.
how is that possible?  shouldn't doing what i described reproduce
the kernel and modules exactly as they were shipped?

  this is very puzzling.

rday