Log Message:
Fix build problem on NetBSD 4.

Previous patch for NetBSD wasn't really for netbsd4 but 4.99.58 and later.
So, I changed "#ifdef netbsd4" to "#ifdef \ 
NETBSD_STATS_VIA_SYSCTL" and
clean up patches.  Should be fix PR pkg/43288.

It is fix of build problem only, so no PKG_REVISION bump.