Add session_start_time external variable that maps to time(NULL) at
session start.
Another tweak to the mem_alloc_tiny() vs. -DDEBUG issue.
Merge branch 'bleeding-jumbo' into memdbg

* bleeding-jumbo:
  Another tweak to the mem_alloc_tiny() vs. -DDEBUG issue.
  Add session_start_time external variable that maps to time(NULL) at session start.

Conflicts:
	src/memory.c