Tighten Safe Haskell bounds, fixes new warning in GHC 7.10.

System/Posix/DynamicLinker/Module.hsc

-#ifdef __GLASGOW_HASKELL__
+#if __GLASGOW_HASKELL__ >= 709
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 703
 {-# LANGUAGE Trustworthy #-}
 #endif
 -----------------------------------------------------------------------------

System/Posix/DynamicLinker/Prim.hsc

 #ifdef __GLASGOW_HASKELL__
 {-# LANGUAGE Trustworthy #-}
+#if __GLASGOW_HASKELL__ >= 709
+{-# OPTIONS_GHC -fno-warn-trustworthy-safe #-}
+#endif
 #endif
 -----------------------------------------------------------------------------
 -- |

System/Posix/Env.hsc

-#ifdef __GLASGOW_HASKELL__
+#if __GLASGOW_HASKELL__ >= 709
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 703
 {-# LANGUAGE Trustworthy #-}
 #endif
 -----------------------------------------------------------------------------

System/Posix/IO.hsc

-#ifdef __GLASGOW_HASKELL__
+#if __GLASGOW_HASKELL__ >= 709
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 703
 {-# LANGUAGE Trustworthy #-}
 #endif
 -----------------------------------------------------------------------------

System/Posix/IO/ByteString.hsc

-#ifdef __GLASGOW_HASKELL__
+#if __GLASGOW_HASKELL__ >= 709
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 703
 {-# LANGUAGE Trustworthy #-}
 #endif
 -----------------------------------------------------------------------------

System/Posix/SharedMem.hsc

-#ifdef __GLASGOW_HASKELL__
+#if __GLASGOW_HASKELL__ >= 709
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 703
 {-# LANGUAGE Trustworthy #-}
 #endif
 -----------------------------------------------------------------------------

System/Posix/Temp.hsc

-#ifdef __GLASGOW_HASKELL__
+#if __GLASGOW_HASKELL__ >= 709
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 703
 {-# LANGUAGE Trustworthy #-}
 #endif
 -----------------------------------------------------------------------------

System/Posix/Temp/ByteString.hsc

-#ifdef __GLASGOW_HASKELL__
+#if __GLASGOW_HASKELL__ >= 709
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 703
 {-# LANGUAGE Trustworthy #-}
 #endif
 -----------------------------------------------------------------------------