Fix struct dirent d_type macro test

cbits/HsUnix.c

@@ -106,7 +106,7 @@ char *__hscore_d_name( struct dirent* d )
 
 char __hscore_d_type( struct dirent* d )
 {
-#ifdef HAVE_DIRENT_D_TYPE
+#ifdef HAVE_STRUCT_DIRENT_D_TYPE
   return (d->d_type);
 #else
   return CONST_DT_UNKNOWN;

tests/DirEntType.hs

@@ -0,0 +1,33 @@
+{-# LANGUAGE LambdaCase #-}
+
+module Main (main) where
+
+import Control.Exception                (bracket)
+import Foreign.C.String                 (peekCString)
+import System.Exit                      (die)
+import System.Posix.Directory
+import System.Posix.Directory.Internals
+import Text.Printf                      (printf)
+
+peekDirEnt :: DirEnt -> IO (String, DirType)
+peekDirEnt dirEnt = do
+    dName <- dirEntName dirEnt >>= peekCString
+    dType <- dirEntType dirEnt
+    return (dName, dType)
+
+testDirTypeOfProcSelf :: DirStream -> IO ()
+testDirTypeOfProcSelf dirStream = go where
+    go = readDirStreamWith peekDirEnt dirStream >>= \case
+        Just (dName, dType) -> case dName of
+            "self" -> case dType of
+                SymbolicLinkType -> return ()
+                _                -> die $
+                    printf "DirEnt of /proc/self has %s; expected %s!"
+                        (show dType)
+                        (show SymbolicLinkType)
+            _ -> go
+        Nothing -> die
+            "Didn't find \"self\" DirEnt while reading /proc DirStream!"
+
+main :: IO ()
+main = bracket (openDirStream "/proc") closeDirStream testDirTypeOfProcSelf

unix.cabal

@@ -382,3 +382,15 @@ test-suite T13660
     else
       build-depends: filepath >= 1.4.100.0 && < 1.5.0.0
     ghc-options: -Wall
+
+test-suite DirEntType
+    if !os(linux)
+        build-depends: unbuildable<0
+        buildable: False
+
+    hs-source-dirs: tests
+    main-is: DirEntType.hs
+    type: exitcode-stdio-1.0
+    default-language: Haskell2010
+    build-depends: base, unix
+    ghc-options: -Wall