There will be more than one function which, in multiarch mode, wants
to use SSSE3. We should not test in each of them for Atoms with
slow SSSE3. Instead, disable the SSSE3 bit in the startup code for
such machines.
Some of the new multi-arch string functions for x86-64 were
not aligned to 16 byte boundarie,s possibly creating unnecessary
cache line misses and delays.
This patch adds SSSE3 strcpy/stpcpy. I got up to 4X speed up on Core 2
and Core i7. I disabled it on Atom since SSSE3 version is slower for
shorter (<64byte) data.
