[patch] m68k: Add constraints.md.

[Kazu Hirata]

Hi Richard,

>> +(define_constraint "W"
>> +  "Used for const_call_operands."
>> +  (match_test "const_call_operand (op, VOIDmode)"))
> 
> Just wondering: does (match_operand "const_call_operand") work here?

Thanks.  I've incorporated this change to my patch.  I'll post an updated 
patch after fixing the RTL sharing problem:

   http://gcc.gnu.org/ml/gcc-patches/2007-04/msg01464.html

Kazu Hirata