Fix signatures of placement operator delete in places where placement

delete is declared. As we don't use exceptions placement delete is never 
called and the fix only affects numerous warnings when
compiling with MS Visual C++.
For more info see http://www.gotw.ca/gotw/010.htm.

sql/item.h

@@ -119,7 +119,7 @@ public:
   static void *operator new(size_t size, MEM_ROOT *mem_root)
   { return (void*) alloc_root(mem_root, (uint) size); }
   static void operator delete(void *ptr,size_t size) {}
-  static void operator delete(void *ptr,size_t size, MEM_ROOT *mem_root) {}
+  static void operator delete(void *ptr, MEM_ROOT *mem_root) {}
 
   enum Type {FIELD_ITEM, FUNC_ITEM, SUM_FUNC_ITEM, STRING_ITEM,
 	     INT_ITEM, REAL_ITEM, NULL_ITEM, VARBIN_ITEM,

sql/sql_class.cc

@@ -707,6 +707,8 @@ struct Item_change_record: public ilink
   Item *old_value;
   /* Placement new was hidden by `new' in ilink (TODO: check): */
   static void *operator new(size_t size, void *mem) { return mem; }
+  static void operator delete(void *ptr, size_t size) {}
+  static void operator delete(void *ptr, void *mem) { /* never called */ }
 };
 
 

sql/sql_lex.h

@@ -241,7 +241,7 @@ public:
   static void *operator new(size_t size, MEM_ROOT *mem_root)
   { return (void*) alloc_root(mem_root, (uint) size); }
   static void operator delete(void *ptr,size_t size) {}
-  static void operator delete(void *ptr,size_t size, MEM_ROOT *mem_root) {}
+  static void operator delete(void *ptr, MEM_ROOT *mem_root) {}
   st_select_lex_node(): linkage(UNSPECIFIED_TYPE) {}
   virtual ~st_select_lex_node() {}
   inline st_select_lex_node* get_master() { return master; }

sql/sql_list.h

@@ -41,8 +41,8 @@ public:
   static void *operator new(size_t size, MEM_ROOT *mem_root)
   { return (void*) alloc_root(mem_root, (uint) size); }
   static void operator delete(void *ptr, size_t size) { TRASH(ptr, size); }
-  static void operator delete(void *ptr, size_t size, MEM_ROOT *mem_root)
-  { TRASH(ptr, size); }
+  static void operator delete(void *ptr, MEM_ROOT *mem_root)
+  { /* never called */ }
   static void operator delete[](void *ptr, size_t size) { TRASH(ptr, size); }
 #ifdef HAVE_purify
   bool dummy;

sql/sql_string.h

@@ -73,7 +73,7 @@ public:
   { return (void*) alloc_root(mem_root, (uint) size); }
   static void operator delete(void *ptr_arg,size_t size)
     {}
-  static void operator delete(void *ptr_arg,size_t size, MEM_ROOT *mem_root)
+  static void operator delete(void *ptr_arg, MEM_ROOT *mem_root)
     {}
   ~String() { free(); }