mysys/ptr_cmp.c:
  Removed old comments
pstack/bucomm.c:
  Change to use mkstemp.
sql/Makefile.am:
  Added Unique class
sql/filesort.cc:
  Changes to let the Unique class use the old filesort code.
sql/sql_class.h:
  Added Unique class
sql/sql_handler.cc:
  Removed warning.
sql/sql_select.cc:
  Cleaned up typo.