>
>It would seem rather obvious to me that using the -m486 flag will allow
>the compiler to include 486-specific instructions in the resulting code.
>If a given program still works on a 386 it is due to luck, and should
>not be depended on.
>
>Since the 386 systems are the slowest of the x86 machines, requiring them
>to recompile in order to be sure the code will work would be rather rude.
>

Just read the gcc man page sometime and you'll learn otherwise:

       These  `-m' options are defined for the Intel 80386 family
       of computers: -m486

       -mno-486
              Control whether or not code is optimized for a  486
              instead  of  an 386.  Code generated for a 486 will
              run on a 386 and vice versa.

In other words it'll work on both just optimized for the 486. Which if I 
remember is just pipeline optimizations anyways.

James