Fixed compiler warnings (Mostly VC++):

- Removed not used variables
- Changed some ulong parameters/variables to ulonglong (possible serious bug)
- Added casts to get rid of safe assignment from longlong to long (and similar)
- Added casts to function parameters
- Fixed signed/unsigned compares
- Added some constructores to structures
- Removed some not portable constructs

Better fix for bug Bug #21428 "skipped 9 bytes from file: socket (3)" on "mysqladmin shutdown"
(Added new parameter to net_clear() to define when we want the communication buffer to be emptied)

client/mysqlslap.c

@@ -979,7 +979,9 @@ drop_schema(MYSQL *mysql, const char *db)
 static int
 run_scheduler(stats *sptr, statement *stmts, uint concur, ulonglong limit)
 {
+#ifndef __WIN__
   uint x;
+#endif
   File lock_file;
   struct timeval start_time, end_time;
   thread_context con;