fixup! Windows builtin toolchain

m4/fp_settings.m4

@@ -6,7 +6,7 @@
 AC_DEFUN([SUBST_TOOLDIR],
 [
     dnl See Note [tooldir: How GHC finds mingw on Windows]
-    $1=`echo $1 | sed 's%'"$mingwpath"'%$$tooldir/mingw%'`
+    $1=`echo $$1 | sed 's%'"$mingwpath"'%$$tooldir/mingw%'`
 ])
 
 # FP_SETTINGS

m4/fp_setup_windows_toolchain.m4

@@ -120,6 +120,8 @@ AC_DEFUN([FP_SETUP_WINDOWS_TOOLCHAIN],[
     RANLIB="${mingwbin}llvm-ranlib.exe"
     OBJDUMP="${mingwbin}llvm-objdump.exe"
     DLLTOOL="${mingwbin}llvm-dlltool.exe"
+    DllWrapCmd="${mingwbin}llvm-dllwrap.exe"
+    WindresCmd="${mingwbin}llvm-windres.exe"
 
     # N.B. LLD does not support -r
     MergeObjsCmd=""

m4/ghc_toolchain.m4

@@ -94,7 +94,7 @@ AC_DEFUN([FIND_GHC_TOOLCHAIN],
     echo "--ar=$AR" >> acargs
     echo "--ranlib=$RANLIB" >> acargs
     echo "--nm=$NM" >> acargs
-    echo "--merge-objs=$SettingsMergeObjectsCommand" >> acargs
+    echo "--merge-objs=$MergeObjsCmd" >> acargs
     echo "--readelf=$READELF" >> acargs
     echo "--windres=$WindresCmd" >> acargs
     echo "--dllwrap=$DllWrapCmd" >> acargs

m4/prep_target_file.m4

@@ -2,7 +2,7 @@
 # =========================
 #
 # Issue a substitution of [$1MaybeProg] with
-# * Nothing, if $1 is /bin/false (this is unfortunately hardcoded since SettingsDllWrapCommand and SettingsWindresCommand get set to this on windows).
+# * Nothing, if $1 is empty
 # * Just (Program {prgPath = "$$1", prgFlags = []}), otherwise
 #
 # $1 = optional value

utils/ghc-toolchain/src/GHC/Toolchain/Monad.hs

@@ -34,6 +34,8 @@ import qualified Control.Monad.Trans.Reader as Reader
 import qualified Control.Monad.Trans.Except as Except
 import System.IO hiding (readFile, writeFile, appendFile)
 -- import qualified System.Directory
+import qualified Data.Text    as T
+import qualified Data.Text.IO as T
 
 
 data Env = Env { verbosity    :: Int
@@ -100,7 +102,7 @@ logMsg v msg = do
     when (verbosity e >= v) (liftIO $ hPutStrLn stderr $ indent ++ msg)
 
 readFile :: FilePath -> M String
-readFile path = liftIO $ Prelude.readFile path
+readFile path = liftIO $ T.unpack <$> T.readFile path
 
 writeFile :: FilePath -> String -> M ()
 writeFile path s = liftIO $ Prelude.writeFile path s