suppress debug printouts in malloc.c

[jiayulu]

Is there a compile-time option to disable debug messages coming from ./ompi/opal/util/malloc.c?

I get a lot of print-outs like this:
malloc debug: Request for 0 bytes (pmix_ext_server_north.c, 414)

The message is actually coming from ./ompi/opal/util/malloc.c

[jsquyres]

They only show up in debug builds. See HACKING.

(also, the building-debug-builds-by-default-for-developers behavior is likely to change in the immediate future -- see #1417)

[rhc54]

It would be appreciated if you pass those along, however, so we can cleanup the code that is the root cause of them