fix the fixes

compiler/GHC/Driver/MakeSem.hs

@@ -212,10 +212,12 @@ cleanupJobserver (Jobserver { jSemaphore = sem
       vcat [ text "about to release all owned semaphore tokens"
            , ppr jobs ]
     -- (-1) because the caller of GHC is responsible for releasing the last slot on the semaphore.
-    tokens_before <- releaseSemaphore sem (owned - 1)
-    logDumpMsg logger "cleanupJobserver }" $
-      vcat [ text "released:" <+> ppr owned
-           , text "semaphore count before release:" <+> ppr tokens_before ]
+    let toks_to_release = owned - 1
+    when (toks_to_release > 0) do
+      tokens_before <- releaseSemaphore sem (owned - 1)
+      logDumpMsg logger "cleanupJobserver }" $
+        vcat [ text "released:" <+> ppr owned
+             , text "semaphore count before release:" <+> ppr tokens_before ]
 
 -- | Dispatch the available tokens acquired from the semaphore
 -- to the pending jobs in the job server.

hadrian/hadrian.cabal

@@ -165,12 +165,11 @@ executable hadrian
                        , unordered-containers >= 0.2.1   && < 0.3
                        , text                 >= 1.2     && < 3
                        , time
-                       , unix
 
     if os(windows)
-        build-depends: Win32
-      else
-        build-depends: unix
+      build-depends: Win32
+    else
+      build-depends: unix
 
     ghc-options:       -Wall
                        -Wincomplete-record-updates