sql/gstream.cc:
  checking for ending \0 changed with m_limit
sql/gstream.h:
  checking for ending \0 changed with m_limit
sql/item_geofunc.cc:
  we should check for null value before we use val_str result
sql/item_strfunc.cc:
  get rid of annoying warnings
sql/spatial.h:
  error about size_t type fixed