defined in my_config.h (as opposed to in CFLAGS before.)

mysys/my_malloc.c:
  Need to include my_global.h before messing with SAFEMALLOC, as now that macro may be
  re-defined in my_config.h, which is included from my_global.h
mysys/my_once.c:
  Need to include my_global.h before messing with SAFEMALLOC, as now that macro may be
  re-defined in my_config.h, which is included from my_global.h
mysys/my_realloc.c:
  Need to include my_global.h before messing with SAFEMALLOC, as now that macro may be
  re-defined in my_config.h, which is included from my_global.h