update (test file has been changed) and improve feedback for check rule

Signed-off-by: Mattias Andrée <maandree@operamail.com>
remove old use of keyword extern

Signed-off-by: Mattias Andrée <maandree@operamail.com>
add benchmark rule

Signed-off-by: Mattias Andrée <maandree@operamail.com>
use `static inline` and not `inline` (seem to increase the performance a little bit)

Signed-off-by: Mattias Andrée <maandree@operamail.com>
on best performance

Signed-off-by: Mattias Andrée <maandree@operamail.com>
portability

Signed-off-by: Mattias Andrée <maandree@operamail.com>
portability

Signed-off-by: Mattias Andrée <maandree@operamail.com>