Fix for #2278 (mysql_prepare and mysql_execute not exported in libmysqld.dll)

Actually no PS-related methods were exported.
Now they're in the libmysqld.def


VC++Files/libmysqld/libmysqld.def:
  PS related methods added

VC++Files/libmysqld/libmysqld.def

@@ -92,6 +92,28 @@ EXPORTS
 	mysql_thread_safe
 	mysql_use_result
 	mysql_warning_count
+	mysql_prepare
+	mysql_execute
+	mysql_param_count
+	mysql_bind_param
+	mysql_bind_result
+	mysql_fetch
+	mysql_fetch_column
+	mysql_send_long_data
+	mysql_get_metadata
+	mysql_param_result
+	mysql_stmt_close
+	mysql_stmt_reset
+	mysql_stmt_free_result
+	mysql_stmt_errno
+	mysql_stmt_error
+	mysql_stmt_sqlstate
+	mysql_stmt_affected_rows
+	mysql_stmt_store_result
+	mysql_stmt_row_seek
+	mysql_stmt_row_tell
+	mysql_stmt_data_seek
+	mysql_stmt_num_rows
 	net_buffer_length
 	set_dynamic
 	strcend