content: $NetBSD: patch-libraries_time_lib_Data_Time_Clock_CTimeval.hs,v 1.1 2019/12/29 16:59:09 pho Exp $
  
  Suppress linker warnings about compatibility syscall wrappers by using
  "capi" instead of "ccall". In Haskell FFI, "ccall" is actually an
  interface to C ABI rather than C API. That is, GHC generates direct
  references to the symbol even if it's actually defined as a cpp macro
  or something like that, because GHC knows nothing about those macros
  in foreign headers. Hence the following warnings:
  
    .../libHStime-1.4.0.1.a(CTimeval.o): In function `s1Kp_info':
    (.text+0x2f): warning: warning: reference to compatibility
    gettimeofday(); include <sys/time.h> to generate correct reference
  
  In other words, you can safely use "ccall" only when you are sure the
  symbol you want to import is actually a symbol in the ABI sense, which
  is not always the case for the POSIX API.
  
  --- libraries/time/lib/Data/Time/Clock/CTimeval.hs.orig	2015-07-23 22:04:53.000000000 +0000
  +++ libraries/time/lib/Data/Time/Clock/CTimeval.hs
  @@ -1,3 +1,4 @@
  +{-# LANGUAGE CApiFFI #-}
   -- #hide
   module Data.Time.Clock.CTimeval where
   
  @@ -24,7 +25,7 @@ instance Storable CTimeval where
   		pokeElemOff (castPtr p) 0 s
   		pokeElemOff (castPtr p) 1 mus
   
  -foreign import ccall unsafe "time.h gettimeofday" gettimeofday :: Ptr CTimeval -> Ptr () -> IO CInt
  +foreign import capi unsafe "sys/time.h gettimeofday" gettimeofday :: Ptr CTimeval -> Ptr () -> IO CInt
   
   -- | Get the current POSIX time from the system clock.
   getCTimeval :: IO CTimeval
  