Put WARNS?=6 in usr.sbin/Makefile.inc (like in usr.bin/ etc.).
-rw-r--r-- 83 .gitignore
-rw-r--r-- 6915 COPYRIGHT
-rw-r--r-- 8457 Makefile
-rw-r--r-- 33435 Makefile.inc1
-rw-r--r-- 47321 Makefile_upgrade.inc
-rw-r--r-- 2599 README
-rw-r--r-- 9293 UPDATING
drwxr-xr-x - bin
drwxr-xr-x - contrib
drwxr-xr-x - crypto
drwxr-xr-x - etc
drwxr-xr-x - games
drwxr-xr-x - gnu
drwxr-xr-x - include
drwxr-xr-x - kerberos5
drwxr-xr-x - lib
drwxr-xr-x - libexec
drwxr-xr-x - nrelease
drwxr-xr-x - sbin
drwxr-xr-x - secure
drwxr-xr-x - share
drwxr-xr-x - sys
drwxr-xr-x - test
drwxr-xr-x - tools
drwxr-xr-x - usr.bin
drwxr-xr-x - usr.sbin