[m-dev.] for review: Aditi [4]

[Zoltan Somogyi]

> > The calls to isalnum() need to cast the argument to unsigned char.
> > Or (better) replace them with calls to MR_isalnum()
> > (which you can copy from the Mercury runtime).
> 
> Where in the Mercury runtime?
> I've done as you suggested anyway.

At the moment, it is at the top of mercury_trace_internal.c, but in
my debugging changes I will move it a new file mercury_macros.h.

Zoltan.