reworked talloc() to in order to help track down invalid

memory access.

Tridge, I don't think using 0xdeadbeef for size allocations
of 0 is going to work.  I ended up having to use NULL
as much code that works on UNISTR checks to see if the buffer ptr
is NULL.  So valid code ends up with a seg fault.

Rather than rewriting it all, I added a DEBUG_TALLOC
#ifdef in talloc.h that sets a macro BAD_PTR.
This is the value assigned to ptr for an allocation of 0 bytes.



jerry
(This used to be commit 233b9cffa2)

source3/include/talloc.h

@@ -21,6 +21,12 @@
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
 
+#ifdef DEBUG_TALLOC
+#define BAD_PTR (void*)0xdeadbeef
+#else
+#define BAD_PTR NULL
+#endif
+
 struct talloc_chunk {
 	struct talloc_chunk *next;
 	void *ptr;