[xml] DEBUG_MEMORY_LOCATION problem

["Wessel" <wessel aule net>]

After recompiling with ./configure --with-mem-debug, my program dumps a
.memdump file every time it quits.  One of the lines from .memdump looks
like:

30 619 3 malloc() in none(0) "IP"

Now I'm trying to get the none(0) replaced with __FILE__ and __LINE__
respectively. I defined DEBUG_MEMORY_LOCATION at the top of my header
file. However, this does not work. GDB says:

  (gdb) break xmlMallocLoc
  Function "xmlMallocLoc" not defined.

To check if the correct #ifdef was triggered, I put "#error 1" just
below #define xmlMalloc(size) xmlMallocLoc((size), __FILE__, __LINE__).
The #error was triggered, so the define of xmlMalloc to xmlMallocLoc
actually occurred.

How is it possible that the #define doesn't work?

TIA,
Wessel