[CM] clm instrument won't compile

[Bill Schottstaedt]

The documentation is correct, unfortunately;  it turned out to be a major
problem to implement generator-type fields in clm-3 -- I spent several days
fussing with it, then gave up.  I had thought it would work in non-CL
clm's, but I seem to be getting an unexpected error in that case too --
groan!  I am willing to translate your clm-2 instrument to run in clm-3.
It might not be as pretty, but there's always a way around the def-clm-struct
restriction.