The remaining architectures at the moment are: ia64, mips, parisc,
s390, um and xtensa. We should probably convert these as well, but

I'm not sure it makes sense to convert um, the implementation uses
strncpy(), and that should use the libc implementation, which is tuned
for the actual hardware that the binary is running on, so performance
wise that might be better.

OTOH, maybe this is all in the noise given the huge syscall overhead in
um, so maybe unifying it would make more sense.

johannes