binary backwards compatibility

[Pádraig Brady <P draigBrady com>]

I was trying to compile a binary on Fedora 7
so that is was portable to as many systems as possible,
but was getting a "Floating point exception" at startup,
on older systems?

I.E. compile the following on Fedora 7:

#include <stdio.h>
int main(void)
{
    printf ("Hello world\n");
    return 0;
}

The resultant binary will throw a floating point exception
at startup on ubuntu breezy and debian sarge at least
(but is Ok on ubuntu feisty).

Note, if I link the binary statically on F7, then it
runs everywhere, though we're told that's a bad idea:
http://people.redhat.com/drepper/no_static_linking.html

Note also, that binaries compiled on Feisty are Ok everywhere.
Pertinent package versions on F7 and Feisty are:
$ dpkg -l libc6 gcc | grep ii
ii  gcc            4.1.2-1ubuntu1 The GNU C compiler
ii  libc6          2.5-0ubuntu14  GNU C Library: Shared libraries
$ rpm -q glibc gcc
glibc-2.6-3
gcc-4.1.2-12

any ideas?

Pádraig.