There are quite a few packages that depend on nasm. This would seem to be a bad thing for PPC machines. The dependency seems like it should be tied to architecture somehow.
Summary of nasm: The Netwide Assembler, a portable x86 assembler with Intel-like syntax This will never make it to ppc (you are right there). Any current builds requiring it that fail on ppc should be reported however as they will need to be fixed/masked. It is not possible to block it as you speak for the whole arch, but needs to be dealt with on a build to build basis :(
