MFC r345499:
Change all kernel C-type macros into static inline functions.

The current kernel C-type macros might obscurely hide the fact that
the input argument might be used multiple times.

This breaks code like:
isalpha(*ptr++)

Use static inline functions instead of macros to fix this.

Reviewed by: kib @
Differential Revision: https://reviews.freebsd.org/D19694
Sponsored by: Mellanox Technologies