sql/item_cmpfunc.h:
  gcc 4.1 linux warning fixes backported from 5.0
sql/opt_range.cc:
  gcc 4.1 linux warning fixes.
sql/spatial.h:
  gcc 4.1 linux warning fixes backported from 5.0
sql/sql_select.h:
  gcc 4.1 linux warning fixes.
sql/sql_update.cc:
  gcc 4.1 linux warning fixes.