NOT implemented system interfaces from the Single Unix Specification, Volume 3:
acoshl
acosl
aio_cancel
aio_error
aio_fsync
aio_read
aio_return
aio_suspend
aio_write
asinhl
asinl
atan2l
atanhl
atanl
bsd_signal
cabsl
cacos
cacosf
cacosh
cacoshf
cacoshl
cacosl
carg
cargf
cargl
casin
casinf
casinh
casinhf
casinhl
casinl
catan
catanf
catanh
catanhf
catanhl
catanl
cbrtl
ccos
ccosf
ccosh
ccoshf
ccoshl
ccosl
ceill
cexp
cexpf
cexpl
cimag
cimagf
cimagl
clock_getcpuclockid
clog
clogf
clogl
conj
conjf
conjl
copysignl
coshl
cosl
cpow
cpowf
cpowl
cproj
cprojf
cprojl
creal
crealf
creall
csin
csinf
csinh
csinhf
csinhl
csinl
csqrt
csqrtf
csqrtl
ctan
ctanf
ctanh
ctanhf
ctanhl
ctanl
endnetent
erfcl
erfl
exp2l
expl
expm1l
fabsl
fattach
fdiml
feclearexcept
fegetenv
fegetexceptflag
fegetround
feholdexcept
feraiseexcept
fesetenv
fesetexceptflag
fesetround
fetestexcept
feupdateenv
fgetwc
fgetws
floorl
fmal
fmaxl
fminl
fmodl
fmtmsg
fputwc
fputws
frexpl
fwide
fwprintf
fwscanf
getcontext
getdate
getdate_err
gethostent
getmsg
getnetbyaddr
getnetbyname
getnetent
getpmsg
getwc
getwchar
hypotl
ilogbl
initstate
isastream
ldexpl
lgammal
lio_listio
llround
llroundf
llroundl
log10l
log1pl
log2l
logbl
logl
lroundl
makecontext
mlockall
modfl
munlockall
nanl
nearbyintl
nextafterl
nexttowardl
posix_mem_offset
posix_spawn[...]
posix_trace[...]
posix_typed_[...]
powl
pthread_attr_getguardsize
pthread_attr_getstack
pthread_attr_getstackaddr
pthread_attr_setguardsize
pthread_attr_setstack
pthread_attr_setstackaddr
pthread_barrier[...]
pthread_condattr_getclock
pthread_condattr_setclock
pthread_getcpuclockid
pthread_mutex_timedlock
pthread_rwlock_timedrdlock
pthread_rwlock_timedwrlock
pthread_setschedprio
pthread_spin_[...]
putmsg
reminderl
remquol
roundl
scalblnl
scalbnl
setcontext
setnetent
sigaltstack
sigtimedwait
sinhl
sinl
sockatmark
sqrtl
strfmon
strtold
swabcontext
swprintf
swscanf
tanhl
tanl
tcgetsid
tgammal
timer_getoverrun
truncl
ulimit
vfwprintf
vfwscanf
vswprintf
vswscanf
vwprintf
vwscanf
waitid
wcsftime
wcstod
wcstof
wcstoimax
wcstok
wcstold
wcstoumax
wcswcs
wordexp
wordfree
wscanf