SET CHARACTER SET DEFAULT didn't work (Bug #462)

BUILD/compile-pentium-debug-max

@@ -3,7 +3,7 @@
 path=`dirname $0`
 . "$path/SETUP.sh"
 
-extra_flags="$pentium_cflags $debug_cflags -DBIG_TABLES"
+extra_flags="$pentium_cflags $debug_cflags"
 c_warnings="$c_warnings $debug_extra_warnings"
 cxx_warnings="$cxx_warnings $debug_extra_warnings"
 extra_configs="$pentium_configs $debug_configs"

mysql-test/r/convert.result

+select @@convert_character_set;
+@@convert_character_set
+
+select @@global.convert_character_set;
+@@global.convert_character_set
+
+show variables like "%convert_character_set%";
+Variable_name	Value
+convert_character_set	
+SET CHARACTER SET cp1251_koi8;
+select @@convert_character_set;
+@@convert_character_set
+cp1251_koi8
+SET CHARACTER SET DEFAULT;
+select @@convert_character_set;
+@@convert_character_set
+

mysql-test/t/convert.test

+# Test of character set conversions
+
+# Test that SET DEFAULT works
+
+select @@convert_character_set;
+select @@global.convert_character_set;
+show variables like "%convert_character_set%";
+SET CHARACTER SET cp1251_koi8;
+select @@convert_character_set;
+SET CHARACTER SET DEFAULT;
+select @@convert_character_set;

sql/set_var.cc

@@ -1083,6 +1083,11 @@ byte *sys_var_thd_conv_charset::value_ptr(THD *thd, enum_var_type type)
 }
 
 
+void sys_var_thd_conv_charset::set_default(THD *thd, enum_var_type type)
+{
+  thd->variables.convert_set= global_system_variables.convert_set; 
+}
+
 
 bool sys_var_timestamp::update(THD *thd,  set_var *var)
 {

sql/set_var.h

@@ -412,6 +412,7 @@ public:
     return type != STRING_RESULT;		/* Only accept strings */
   }
   bool check_default(enum_var_type type) { return 0; }
+  void set_default(THD *thd, enum_var_type type);
 };