asm clobbers, !SMALL_REGISTER_CLASSES patch.

[David Edelsohn]

        * stmt.c (expand_asm_operands): When an asm statement
        clobbers a register that is in a class of its own, and there
        is space remaining for an extra output, turn the clobber into
        an output to a dummy pseudo.  At present, don't do this if
        there are constraints that have alternatives.

	This is a good effort and I am glad that you are continuing to
pursue this needed feature, but I am curious why you are choosing to
implement it this way instead of as a match_scratch of the appropriate
register class?  I think that the correct solution is to turn the clobber
of a named register into the equivalent that GCC uses internally for
machine description files: match_scratch.  This patch probably works to
some extent, but it simply lies to GCC by transforming the clobber -- and
lying to GCC always causes problems in the long run.

David