Make `-Wall` clean and drop `-fno-warn-unused-imports`

CPP conditional code sections have been carefully taken into account
while performing this warning cleanup. Most `OPTIONS_GHC` declarations
could be dropped (now only a lonely `{-# OPTIONS_GHC -fno-cse #-}`
remains in `Posix.Signals`).

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>

2 files changed, 8 insertions, 17 deletions

diff --git a/System/Posix/Terminal/ByteString.hsc b/System/Posix/Terminal/ByteString.hsc
index a667c8a..ad2dd26 100644
--- a/System/Posix/Terminal/ByteString.hsc
+++ b/System/Posix/Terminal/ByteString.hsc
@@ -1,4 +1,3 @@
-{-# OPTIONS_GHC -fno-warn-unused-imports #-}
 #ifdef __GLASGOW_HASKELL__
 {-# LANGUAGE Trustworthy #-}
 #endif
@@ -75,8 +74,10 @@ module System.Posix.Terminal.ByteString (
 import Foreign
 import System.Posix.Types
 import System.Posix.Terminal.Common
-import System.Posix.IO.ByteString
-import Data.ByteString.Char8 as B
+#ifndef HAVE_OPENPTY
+import System.Posix.IO.ByteString (defaultFileFlags, openFd, noctty, OpenMode(ReadWrite))
+import Data.ByteString.Char8 as B ( pack, )
+#endif
 
 import Foreign.C hiding (
      throwErrnoPath,
@@ -185,9 +186,9 @@ foreign import ccall unsafe "__hsunix_unlockpt"
   c_unlockpt :: CInt -> IO CInt
 #else
 c_grantpt :: CInt -> IO CInt
-c_grantpt _ = return (fromIntegral 0)
+c_grantpt _ = return (fromIntegral (0::Int))
 
 c_unlockpt :: CInt -> IO CInt
-c_unlockpt _ = return (fromIntegral 0)
+c_unlockpt _ = return (fromIntegral (0::Int))
 #endif /* HAVE_PTSNAME */
 #endif /* !HAVE_OPENPTY */
diff --git a/System/Posix/Terminal/Common.hsc b/System/Posix/Terminal/Common.hsc
index 2a07e28..4075ba3 100644
--- a/System/Posix/Terminal/Common.hsc
+++ b/System/Posix/Terminal/Common.hsc
@@ -1,4 +1,3 @@
-{-# OPTIONS_GHC -fno-warn-unused-imports #-}
 #ifdef __GLASGOW_HASKELL__
 {-# LANGUAGE Trustworthy #-}
 #endif
@@ -69,22 +68,13 @@ module System.Posix.Terminal.Common (
 
 import Data.Bits
 import Data.Char
-import Foreign.C.Error ( errnoToIOError, throwErrnoIfMinus1,
-                         throwErrnoIfMinus1_, throwErrnoIfNull )
-#ifndef HAVE_PTSNAME
-import Foreign.C.Error ( eNOSYS )
-#endif
-import Foreign.C.String ( CString, peekCString, withCString )
+import Foreign.C.Error ( throwErrnoIfMinus1, throwErrnoIfMinus1_ )
 import Foreign.C.Types
 import Foreign.ForeignPtr ( ForeignPtr, withForeignPtr, mallocForeignPtrBytes )
-import Foreign.Marshal.Alloc ( alloca )
 import Foreign.Marshal.Utils ( copyBytes )
-import Foreign.Ptr ( Ptr, nullPtr, plusPtr )
+import Foreign.Ptr ( Ptr, plusPtr )
 import Foreign.Storable ( Storable(..) )
-import System.IO.Error ( ioError )
 import System.IO.Unsafe ( unsafePerformIO )
-import System.Posix.IO ( OpenFileFlags(..), OpenMode(..), defaultFileFlags,
-                         openFd )
 import System.Posix.Types
 
 -- -----------------------------------------------------------------------------