multiple isa support

[Ben Elliston]

   I'm guessing the way to go is to have a separate #include for each decoder.

Right -- that would make sense.  Do we really need to emit a decoder for
each *isa* rather than each CPU?

   After quick glance at m32r's decode.h and decodex.h it seems like they
   can co-exist.  Whether decoders for different isas can co-exist, I
   dunno; I'd have to see them first.

   Which suffix are you refering to?

The suffix that the Makefile appends to the generated files -- for example
the `x' in m32rx.

Ben