(manual port from 4.0 - was needed)

Fix for BUG#4971 "CREATE TABLE ... TYPE=HEAP SELECT ... stops slave (wrong DELETE in binlog)":
replacing the no_log argument of mysql_create_table() by some safer method
(temporarily setting OPTION_BIN_LOG to 0) which guarantees that even the automatic
DELETE FROM heap_table does not get into the binlog when a not-yet-existing HEAP table
is opened by mysql_create_table().

sql/sql_class.h

@@ -1017,6 +1017,27 @@ public:
 #define SYSTEM_THREAD_SLAVE_IO 2
 #define SYSTEM_THREAD_SLAVE_SQL 4
 
+/*
+  Disables binary logging for one thread, and resets it back to what it was
+  before being disabled. 
+  Some functions (like the internal mysql_create_table() when it's called by
+  mysql_alter_table()) must NOT write to the binlog (binlogging is done at the
+  at a later stage of the command already, and must be, for locking reasons);
+  so we internally disable it temporarily by creating the Disable_binlog
+  object and reset the state by destroying the object (don't forget that! or
+  write code so that the object gets automatically destroyed when leaving a
+  function...).
+*/
+class Disable_binlog {
+private:
+  THD *thd;
+  ulong save_options;
+  ulong save_master_access;
+public:
+  Disable_binlog(THD *thd_arg);
+  ~Disable_binlog();
+};
+
 /*
   Used to hold information about file and file structure in exchainge 
   via non-DB file (...INTO OUTFILE..., ...LOAD DATA...)