Included <sys/vnode.h> and its prerequisite <sys/proc.h>, and cleaned
up includes. The vop_t changes made the non-inclusion of vnode.h
fatal instead of just sloppy.
i386_bitops.h:
Changed `extern inline' to `static inline'. `extern inline' is a
Linuxism that stops things from compiling without -O. Fixed
idempotency identifier.
Misc:
Added prototypes. Staticized some functions so that prototypes are
unnecessary. Added casts. Cleaned up includes.