Q: Optimisation

[mirabilos]

Hello,
if I want to compile a complete linux system
with the new-style CFLAGS and kernel opts so
that it RUNS on 486DX and is OPTIMISED for
Pentium, which options do I have to choose in

 - kernel config  (in 2.0.33 I used 586 for this, but since
                    2.2 I can't be sure that it runs on 486 then)

 - kernel CFLAGS
 - user CFLAGS

I think of CFLAGS=-march=i586 -mcpu=i486 -Os -fomit-frame-pointer -Wall

Do programmes compiled so really run on a 486 w/ FPU, and can I use
these CFLAGS (-Os e.g. instead of -O2) for the kernel?

I really want _small_ code (e.g. for floppy systems) and it doesn't
need to be the super-fastest, but it simply has to work.

TIA
-mirabilos