> > Non-working XF4.2.0 sounds highly undesirable...
> 
> XFree86 4.2.0 works with the *default* math library. The problem only
> shows up when you rebuild your math library with "I387_LIBM" set to "YES".

Not quite: the typical setup (IIRC the one we install by default since quite
some time, including 1.5) is:

# cat /etc/ld.so.conf 
libm.so.0       machdep.fpu_present     1:libm387.so.0,libm.so.0

This will make XFree 4.2 fail.

Either install a new libm387.so.* or remove that line from /etc/ld.so.conf.

Martin