[m-dev.] for review: generating traces

[Thomas Charles CONWAY]

Zoltan Somogyi, you write:
> 
> compiler/call_gen.m:
> 	Clean up the generation of code for calls, merging the three
> 	predicates for det, semi and non procedures into one, and factoring
> 	out some common code between the generation of code for normal calls
> 	and higher order calls. Add code to reset the call depth just before
> 	each (normal or higher-order) call if --generate-trace is on.

Just a note - it is better (if possible) to separate changes into
separate diffs/commits. You know this, of course! ;-)

The diff itself looks fine.

Thomas
-- 
ZZ:wq!
^X^C
Thomas Conway               				      conway at cs.mu.oz.au
AD DEUM ET VINUM	  			      Every sword has two edges.