Almost all architectures are setting DECR_PC_AFTER_BREAK to zero, this 
makes that value the default.

The main exception is i386, and even that has an exception to the 
exception - Neutrino.  For Neutrino I've left the set-to-zero as is so 
that it's clear that it is overriding the i386.

baring comments I'll look to commit this in a few days,
Andrew