From: "Zhu, Yi" <yi.zhu@intel.com>

The "make rpm" rule in top Makefile isn't aware of the enviorment ARCH.  For
example, people issue "make ARCH=ia64" to compile the ia64 kernel on i386
platform for cross compilation.  This works pretty well now.  But if one uses
"make rpm ARCH=ia64", it will fail.  Because current rpm rule in Makefile and
mkspec are not aware of ARCH.