Merge with 5.1-microseconds

A lot of small fixes and new test cases.

client/mysqlbinlog.cc:
  Cast removed
client/mysqltest.cc:
  Added missing DBUG_RETURN
include/my_pthread.h:
  set_timespec_time_nsec() now only takes one argument
mysql-test/t/date_formats.test:
  Remove --disable_ps_protocl as now also ps supports microseconds
mysys/my_uuid.c:
  Changed to use my_interval_timer() instead of my_getsystime()
mysys/waiting_threads.c:
  Changed to use my_hrtime()
sql/field.h:
  Added bool special_const_compare() for fields that may convert values before compare (like year)
sql/field_conv.cc:
  Added test to get optimal copying of identical temporal values.
sql/item.cc:
  Return that item_int is equal if it's positive, even if unsigned flag is different.
  Fixed Item_cache_str::save_in_field() to have identical null check as other similar functions
  Added proper NULL check to Item_cache_int::save_in_field()
sql/item_cmpfunc.cc:
  Don't call convert_constant_item() if there is nothing that is worth converting.
  Simplified test when years should be converted
sql/item_sum.cc:
  Mark cache values in Item_sum_hybrid as not constants to ensure they are not replaced by other cache values in compare_datetime()
sql/item_timefunc.cc:
  Changed sec_to_time() to take a my_decimal argument to ensure we don't loose any sub seconds.
  Added Item_temporal_func::get_time() (This simplifies some things)
sql/mysql_priv.h:
  Added Lazy_string_decimal()
sql/mysqld.cc:
  Added my_decimal constants max_seconds_for_time_type, time_second_part_factor
sql/table.cc:
  Changed expr_arena to be of type CONVENTIONAL_EXECUTION to ensure that we don't loose any items that are created by fix_fields()
sql/tztime.cc:
  TIME_to_gmt_sec() now sets *in_dst_time_gap in case of errors
  This is needed to be able to detect if timestamp is 0
storage/maria/lockman.c:
  Changed from my_getsystime() to set_timespec_time_nsec()
storage/maria/ma_loghandler.c:
  Changed from my_getsystime() to my_hrtime()
storage/maria/ma_recovery.c:
  Changed from my_getsystime() to mmicrosecond_interval_timer()
storage/maria/unittest/trnman-t.c:
  Changed from my_getsystime() to mmicrosecond_interval_timer()
storage/xtradb/handler/ha_innodb.cc:
  Added support for new time,datetime and timestamp
unittest/mysys/thr_template.c:
  my_getsystime() -> my_interval_timer()
unittest/mysys/waiting_threads-t.c:
  my_getsystime() -> my_interval_timer()

sql/sql_parse.cc

@@ -1021,18 +1021,6 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
   thd->query_plan_flags= QPLAN_INIT;
   thd->lex->sql_command= SQLCOM_END; /* to avoid confusing VIEW detectors */
   thd->set_time();
-  if (!thd->is_valid_time())
-  {
-    /*
-     If the time has got past 2038 we need to shut this server down
-     We do this by making sure every command is a shutdown and we 
-     have enough privileges to shut the server down
-
-     TODO: remove this when we have full 64 bit my_time_t support
-    */
-    thd->security_ctx->master_access|= SHUTDOWN_ACL;
-    command= COM_SHUTDOWN;
-  }
 
   VOID(pthread_mutex_lock(&LOCK_thread_count));
   thd->query_id= global_query_id;
@@ -1435,10 +1423,7 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
       packet[0].
     */
     enum mysql_enum_shutdown_level level;
-    if (!thd->is_valid_time())
-      level= SHUTDOWN_DEFAULT;
-    else
-      level= (enum mysql_enum_shutdown_level) (uchar) packet[0];
+    level= (enum mysql_enum_shutdown_level) (uchar) packet[0];
     if (level == SHUTDOWN_DEFAULT)
       level= SHUTDOWN_WAIT_ALL_BUFFERS; // soon default will be configurable
     else if (level != SHUTDOWN_WAIT_ALL_BUFFERS)
@@ -5792,6 +5777,7 @@ void mysql_reset_thd_for_next_command(THD *thd, my_bool calculate_userstat)
   thd->stmt_depends_on_first_successful_insert_id_in_prev_stmt= 0;
 
   thd->query_start_used= 0;
+  thd->query_start_sec_part_used= 0;
   thd->is_fatal_error= thd->time_zone_used= 0;
   /*
     Clear the status flag that are expected to be cleared at the
@@ -6251,17 +6237,6 @@ bool add_field_to_list(THD *thd, LEX_STRING *field_name, enum_field_types type,
     DBUG_RETURN(1);
   }
 
-  if (type == MYSQL_TYPE_TIMESTAMP && length)
-  {
-    /* Display widths are no longer supported for TIMSTAMP as of MySQL 4.1.
-       In other words, for declarations such as TIMESTAMP(2), TIMESTAMP(4),
-       and so on, the display width is ignored.
-    */
-    char buf[32];
-    my_snprintf(buf, sizeof(buf), "TIMESTAMP(%s)", length);
-    WARN_DEPRECATED(thd, "6.0", buf, "'TIMESTAMP'");
-  }
-
   if (!(new_field= new Create_field()) ||
       new_field->init(thd, field_name->str, type, length, decimals, type_modifier,
                       default_value, on_update_value, comment, change,