Compund units in extensions

[Robert John Andersen <anderman@anderware.com>]

In assembling the compound unit does the tag in the link specification match
the tag in the exports argument?  So if I have a compound unit composed of
the 2 following units:

  A: no imports, exports a1 and a2
  B: no imports, exports b1

would the links specification be (A ((A a1 a2) (B b1))) and the exports
argument ((A (a1 a2) (B b1)).

Also, how do the units specified in make_compound_unit match up with the
information in the assembly?

Thanks.
RJA