include/Makefile.am:
  Make my_valgrind.h global (as it's used by my_global.h)
include/my_global.h:
  Include my_valgrind.h
include/my_sys.h:
  TRASH() moved to my_valgrind.h
include/my_valgrind.h:
  Add VALGRIND defines to mark memory
mysys/my_alloc.c:
  Mark internal freed memory as undefined