Bug#31177: Server variables can't be set to their current values

Default values of variables were not subject to upper/lower bounds
and step, while setting variables was. Bounds and step are also
applied to defaults now; defaults are corrected quietly, values
given by the user are corrected, and a correction-warning is thrown
as needed. Lastly, very large values could wrap around, starting
from 0 again. They are bounded at the maximum value for the
respective data-type now if no lower maximum is specified in the
variable's definition.


client/mysql.cc:
  correct maxima in options array
client/mysqltest.c:
  adjust minimum for "sleep" option so default value is no longer
  out of bounds.
include/m_string.h:
  ullstr() - the unsigned brother of llstr()
include/my_getopt.h:
  Flag if we bounded the value (that is, correct anything aside from
  making value a multiple of block-size)
mysql-test/r/delayed.result:
  We throw a warning now when we adjust out of range parameters.
mysql-test/r/index_merge.result:
  We throw a warning now when we adjust out of range parameters.
mysql-test/r/innodb.result:
  We throw a warning now when we adjust out of range parameters.
mysql-test/r/innodb_mysql.result:
  We throw a warning now when we adjust out of range parameters.
mysql-test/r/key_cache.result:
  We throw a warning now when we adjust out of range parameters.
mysql-test/r/packet.result:
  We throw a warning now when we adjust out of range parameters.
mysql-test/r/ps.result:
  We throw a warning now when we adjust out of range parameters.
mysql-test/r/subselect.result:
  We throw a warning now when we adjust out of range parameters.
mysql-test/r/type_bit.result:
  We throw a warning now when we adjust out of range parameters.
mysql-test/r/type_bit_innodb.result:
  We throw a warning now when we adjust out of range parameters.
mysql-test/r/variables.result:
  correct results: bounds and step apply to variables' default values, too
mysql-test/t/variables.test:
  correct results: bounds and step apply to variables' default values, too
mysys/my_getopt.c:
  - apply bounds/step to default values of variables (based on work by serg)
  - print complaints about incorrect values for variables (truncation etc.,
    by requestion of consulting)
  - if no lower maximum is specified in variable definition, bound unsigned
    values at their maximum to prevent wrap-around
  - some calls to error_reporter had a \n, some didn't. remove \n from calls,
    let reporter-function handle it, so the default reporter behaves like that
    in mysqld
sql/mysql_priv.h:
  correct RANGE_ALLOC_BLOCK_SIZE (cleared with monty)
sql/mysqld.cc:
  correct maxima to correct data-type.
  correct minima where higher than default.
  correct range-alloc-block-size.
  correct inno variables so GET_* corresponds to actual variable's type.
sql/set_var.cc:
  When the new value for a variable is out of bounds, we'll send the
  client a warning (but not if the value was simply not a multiple of
  'blocksize').  sys_var_thd_ulong had this, sys_var_long_ptr_global
  didn't; broken out and streamlined to avoid duplication of code.
strings/llstr.c:
  ullstr() - the unsigned brother of llstr()

mysql-test/r/innodb_mysql.result

@@ -712,6 +712,8 @@ INSERT INTO t1(b,c) SELECT b,c FROM t2;
 UPDATE t2 SET c='2007-01-03';
 INSERT INTO t1(b,c) SELECT b,c FROM t2;
 set @@sort_buffer_size=8192;
+Warnings:
+Warning	1292	Truncated incorrect sort_buffer_size value: '8192'
 SELECT COUNT(*) FROM t1;
 COUNT(*)
 3072