1 files changed, 13 insertions, 1 deletions
diff --git a/compiler/main/SysTools.lhs b/compiler/main/SysTools.lhs
index 00311597d8..4a51b313e2 100644
--- a/compiler/main/SysTools.lhs
+++ b/compiler/main/SysTools.lhs
@@ -582,10 +582,22 @@ copyWithHeader dflags purpose maybe_header from to = do
   hout <- openBinaryFile to   WriteMode
   hin  <- openBinaryFile from ReadMode
   ls <- hGetContents hin -- inefficient, but it'll do for now. ToDo: speed up
-  maybe (return ()) (hPutStr hout) maybe_header
+  maybe (return ()) (header hout) maybe_header
   hPutStr hout ls
   hClose hout
   hClose hin
+ where
+#if __GLASGOW_HASKELL__ >= 702
+  -- write the header string in UTF-8.  The header is something like
+  --   {-# LINE "foo.hs" #-}
+  -- and we want to make sure a Unicode filename isn't mangled.
+  header h str = do
+   hSetEncoding h utf8
+   hPutStr h str
+   hSetBinaryMode h True
+#else
+  header h str = hPutStr h str
+#endif
 
 -- | read the contents of the named section in an ELF object as a
 -- String.