This came about when refactoring for the new cycle phase mechanism.

   This allows them to work in N_module mode, as they are
   not usable in N_fundef mode.

2. Add DBUG_PRINT statements to SISI. 

SISI is still broken. It doesn't seem to take kindly to
sacprelude functions, and it happily removes all their arguments.
So, SISI remains disabled by default, at least for now.

code of the specified function.

  to get memory usage statistics you now have to turn on memcheck, 
    which is only available on the development version of the compiler.
changed ifdef property of ast.xml to ifndef, in order to replace the SHOW_MALLOC
  macro with DEBUG_OFF. This way, the check memory traversal is not compiled
  in the production version of the compiler.

Semantics are now claimed to be:

    x', y', z', ... = _guard_( x, y, z, ..., p);

If p is true, then x' = x; y' = y; z' = z; 
Otherwise, an error is raised.

This is documented in ~/tex/manaul/built_in_ops.tex.

1. Introduce Loop And Conditional Scalarization (LACS).
   This is basically an extended version of LS, which will work
   on all LACFUNs, whereas LS only works on LOOPFUNs.

   When this stabilizes, I plan to make it scalarize ALL small
   arrays. One step at a time...

   For the time being, LS and LACS are both present in CYC/SAACYC,
   but LACS is disabled by default.
 
2. Slight change to an AL DBUG_PRINT, so we can tell one message
   from the other.