Fix for shutdown on Mac OS X


include/my_tree.h:
  Try to optimize the cache buffer size needed for bulk_insert
myisam/mi_write.c:
  Try to optimize the cache buffer size needed for bulk_insert
mysql-test/r/bdb.result:
  Make test repeatable
mysql-test/t/bdb.test:
  Make test repeatable
mysys/tree.c:
  Try to optimize the cache buffer size needed for bulk_insert
sql/mysql_priv.h:
  Small optimization
sql/mysqld.cc:
  Fix for shutdown on Mac OS X
sql/sql_insert.cc:
  Try to optimize the cache buffer size needed for bulk_insert
sql/sql_yacc.yy:
  Call thd->strmake() instead of sql_strmake()
sql/table.cc:
  Try to optimize the cache buffer size needed for bulk_insert
sql/table.h:
  Try to optimize the cache buffer size needed for bulk_insert