[m-dev.] pbs to run programs under the external debugger

[Zoltan Somogyi]

> Everything is (now) compiling ok (the compiler and mercury programs).
> The problem is that when I execute programs under *my_mdb* (where my_mdb
> ~ mdb[-Di/-De]), it runs the internal debugger instead of the external
> one.

The two causes I can think of are (1) mistake in my_mdb, so that
MERCURY_OPTIONS gets either only -Di or both -De and -Di, and (2)
using a version of mercury_trace.o that was compiled without
-DMR_USE_EXTERNAL_DEBUGGER. You can set breakpoints in gdb
on process_options to check whether (1) is happening
and on MR_trace_event to check whether (2) is happening.

> Did you recently change the way options are handled by chance ?

No, although I got rid of some obsolete options.

> ps: when that problem is fix, I should probably submit my changes (it is
> not the first time I spend time to catch a *rontla* train :-( ).

Great.

Zoltan.