Enable SSE registers by default?

[Kevin Buettner <kevinb@redhat.com>]

The function i386_gdbarch_init() in i386-tdep.c contains the following
comment/code:

  /* The i386 default settings don't include the SSE registers.
     FIXME: kettenis/20020614: They do include the FPU registers for
     now, which probably is not quite right.  */
  tdep->num_xmm_regs = 0;

I would like to see the SSE registers enabled by default, or, if
that proves to be undesirable for some reason, we should have some
way of enabling them for targets which support them.  (Note that
i386-linux-tdep.c enables SSE register support unconditionally.)

The only drawback that I'm aware of with enabling them by default is
that they'll be displayed in ``info all-registers'' even for devices
which don't have these registers.  But, I think they'll always show up
as zero (for remote targets anyway), which is the same behavior that
I'd expect to see for FPU-less cores.  I think this is the reason behind
Mark's FIXME comment.

Is anyone aware of any other drawbacks?

Kevin