Here's the situation. I have a system that's been running for many years
with an Athlon 5050e processor. The system is built with

CFLAGS="-march=k8-sse3 -O2 -pipe -msse3"
CPU_FLAGS_X86="3dnow 3dnowext mmx mmxext sse sse2 sse3"

I have the possibility of upgrading the system to a first-generation Intel
Core i5 which should give a nice speed boost, but of course the Intel chip
doesn't understand 3dnow or 3dnowext, so I'll have to do a system rebuild
before I switch out the motherboard/processor. It seems pretty obvious that
I have to take "3dnow 3dnowext" out of CPU_FLAGS_X86, but what CFLAGS would
be recommended for a system that will still run with the AMD processor but
won't fall over when I switch to the Intel processor? Once I have the Intel
in place I can rebuild with options more suited for that chip, but I want
to make sure I don't end up in a catch-22 situation.

-- 
Manuel A. McLure WW1FA <manuel@mclure.org> <http://www.mclure.org>
...for in Ulthar, according to an ancient and significant law,
no man may kill a cat.                       -- H.P. Lovecraft