System interfaces compatible with BSD functions:
alphasort
bindresvport
bindresvport_sa
cfmakeraw
daemon
dn_comp
dn_expand
dn_skipname
drem
endusershell
err
errx
finite
finitef
fiprintf
flock
forkpty
freeifaddrs
fstatfs
fts_children
fts_close
fts_get_clientptr
fts_get_stream
fts_open
fts_read
fts_set
fts_set_clientptr
funopen
gamma
gamma_r
gammaf
gammaf_r
getdtablesize
getifaddrs
getpagesize
getpeereid
getprogname
getusershell
herror
inet_aton
inet_makeaddr
inet_netof
inet_network
initgroups
iruserok
iruserok_sa
login
login_tty
logout
logwtmp
mkdtemp
openpty
rcmd
rcmd_af
res_close
res_init
res_mkquery
res_nclose
res_ninit
res_nmkquery
res_nquery
res_nquerydomain
res_nsearch
res_nsend
res_query
res_querydomain
res_search
res_send
revoke
rexec
rresvport
rresvport_af
ruserok
sbrk
setbuffer
setgroups
setlinebuf
setpassent
setprogname
settimeofday
setusershell
statfs
strcasestr
strlcat
strlcpy
strsep
strsignal
updwtmp
valloc
verr
verrx
vhangup (see chapter "Implementation Notes")
vsyslog
vwarn
vwarnx
wait3
wait4
warn
warnx
wcslcat
wcslcpy