x.tp_buf was declared as a uint8_t array, but always used as
a char array (which needed a lot of type casts).
The patch includes these changes:
* Fix declaration of x.tp_buf and remove all type casts.
* Use offsetof() to get the offset of x.tp_buf.
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>