Don't read MyISAM header when running without locking


include/myisam.h:
  Don't read header when running without locking.
myisam/mi_locking.c:
  Don't update changed flag for temporary files.
myisam/mi_open.c:
  Don't read header when running without locking.
myisam/mi_static.c:
  Don't read header when running without locking.
sql/item_sum.cc:
  Don't write rows in MyISAM tables when using count(distinct)
sql/mysqld.cc:
  Don't read MyISAM header when running without locking.
  Remove -Sg option.
sql/sql_analyse.h:
  Remove duplicate header.
sql/sql_select.cc:
  Cleaned up prototypes.
  Don't write rows to count(DISTINCT) MyISAM tables.
sql/sql_select.h:
  Cleaned up prototypes.
sql/table.h:
  A
BitKeeper/etc/logging_ok:
  Logging to logging@openlogging.org accepted