Fixed compiler warnings detected by option -Wshadow and -Wunused:

- Removed not used variables and functions
- Added #ifdef around code that is not used
- Renamed variables and functions to avoid conflicts
- Removed some not used arguments

Fixed some class/struct warnings in ndb
Added define IS_LONGDATA() to simplify code in libmysql.c

I did run gcov on the changes and added 'purecov' comments on almost all lines that was not just variable name changes

sql/sql_insert.cc

@@ -60,7 +60,6 @@
 #include "sql_trigger.h"
 #include "sql_select.h"
 
-static int check_null_fields(THD *thd,TABLE *entry);
 #ifndef EMBEDDED_LIBRARY
 static TABLE *delayed_get_table(THD *thd,TABLE_LIST *table_list);
 static int write_delayed(THD *thd,TABLE *table, enum_duplicates dup, bool ignore,
@@ -131,11 +130,11 @@ static int check_insert_fields(THD *thd, TABLE_LIST *table_list,
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
     if (grant_option)
     {
-      Field_iterator_table fields;
-      fields.set_table(table);
+      Field_iterator_table field_it;
+      field_it.set_table(table);
       if (check_grant_all_columns(thd, INSERT_ACL, &table->grant,
                                   table->s->db, table->s->table_name,
-                                  &fields))
+                                  &field_it))
         return -1;
     }
 #endif
@@ -320,8 +319,6 @@ bool mysql_insert(THD *thd,TABLE_LIST *table_list,
     By default, both logs are enabled (this won't cause problems if the server
     runs without --log-update or --log-bin).
   */
-  bool log_on= (thd->options & OPTION_BIN_LOG) ||
-    (!(thd->security_ctx->master_access & SUPER_ACL));
   bool transactional_table, joins_freed= FALSE;
   bool changed;
   uint value_count;
@@ -335,6 +332,8 @@ bool mysql_insert(THD *thd,TABLE_LIST *table_list,
   Name_resolution_context_state ctx_state;
 #ifndef EMBEDDED_LIBRARY
   char *query= thd->query;
+  bool log_on= (thd->options & OPTION_BIN_LOG) ||
+    (!(thd->security_ctx->master_access & SUPER_ACL));
 #endif
   thr_lock_type lock_type = table_list->lock_type;
   Item *unused_conds= 0;
@@ -758,7 +757,6 @@ static bool check_view_insertability(THD * thd, TABLE_LIST *view)
   Field_translator *trans_start= view->field_translation,
 		   *trans_end= trans_start + num;
   Field_translator *trans;
-  Field **field_ptr= table->field;
   uint used_fields_buff_size= (table->s->fields + 7) / 8;
   uchar *used_fields_buff= (uchar*)thd->alloc(used_fields_buff_size);
   MY_BITMAP used_fields;