[PING] Optimize manual byte swap implementations using the GCC bswap builtin

[Andreas Krebbel]

Hi Richard,

> How about building (accumulated) bit-transfer matrices starting off
> interesting statements by simulating them and then
> base the recognition on them?

I already thought about something like this to cover other bswap 
implementations but found it rather tricky to implement. I'll not be 
able to come up with a patch in the foreseeable future. How about going 
with the current version of the patch until a more generic 
implementation is available and reverting my stuff then? The current 
version shouldn't hurt and helps the kernel and glibc.

Bye,

-Andreas-