diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -7,6 +7,8 @@
   * (1.18.3): further rewrites of the #if expression parser
   * (1.18.4): fix the accidental flipping of comment-stripping behaviour
               with --cpp -traditional flags
+  * (1.18.5): fix a bug with windows filepath directory separators in a
+              #include
 
 
 Version 1.17
diff --git a/Language/Preprocessor/Cpphs/Position.hs b/Language/Preprocessor/Cpphs/Position.hs
--- a/Language/Preprocessor/Cpphs/Position.hs
+++ b/Language/Preprocessor/Cpphs/Position.hs
@@ -17,6 +17,7 @@
   , addcol, newline, tab, newlines, newpos
   , cppline, haskline, cpp2hask
   , filename, lineno, directory
+  , cleanPath
   ) where
 
 import Data.List (isPrefixOf)
@@ -38,7 +39,7 @@
 
 -- | Constructor.  Argument is filename.
 newfile :: String -> Posn
-newfile name = Pn name 1 1 Nothing
+newfile name = Pn (cleanPath name) 1 1 Nothing
 
 -- | Increment column number by given quantity.
 addcol :: Int -> Posn -> Posn
@@ -96,4 +97,11 @@
 dirname  = reverse . safetail . dropWhile (not.(`elem`"\\/")) . reverse
   where safetail [] = []
         safetail (_:x) = x
+
+-- | Sigh.  Mixing Windows filepaths with unix is bad.  Make sure there is a
+--   canonical path separator.
+cleanPath :: FilePath -> FilePath
+cleanPath [] = []
+cleanPath ('\\':cs) = '/': cleanPath cs
+cleanPath (c:cs)    = c:   cleanPath cs
 
diff --git a/Language/Preprocessor/Cpphs/ReadFirst.hs b/Language/Preprocessor/Cpphs/ReadFirst.hs
--- a/Language/Preprocessor/Cpphs/ReadFirst.hs
+++ b/Language/Preprocessor/Cpphs/ReadFirst.hs
@@ -19,7 +19,7 @@
 import System.Directory (doesFileExist)
 import Data.List      (intersperse)
 import Control.Monad     (when)
-import Language.Preprocessor.Cpphs.Position  (Posn,directory)
+import Language.Preprocessor.Cpphs.Position  (Posn,directory,cleanPath)
 
 -- | Attempt to read the given file from any location within the search path.
 --   The first location found is returned, together with the file content.
@@ -46,8 +46,9 @@
                            ++"\n  Asked for by: "++show demand)
         return ("missing file: "++name,"")
     try (p:ps) = do
-        let file = p++'/':name
+        let file = cleanPath p++'/':cleanPath name
         ok <- doesFileExist file
         if not ok then try ps
           else do content <- readFile file
                   return (file,content)
+
diff --git a/Language/Preprocessor/Cpphs/RunCpphs.hs b/Language/Preprocessor/Cpphs/RunCpphs.hs
--- a/Language/Preprocessor/Cpphs/RunCpphs.hs
+++ b/Language/Preprocessor/Cpphs/RunCpphs.hs
@@ -13,6 +13,7 @@
 import Language.Preprocessor.Cpphs.Options  (CpphsOptions(..), BoolOptions(..)
                                             ,trailing)
 import Language.Preprocessor.Cpphs.Tokenise (deWordStyle, tokenise)
+import Language.Preprocessor.Cpphs.Position (cleanPath)
 import Language.Preprocessor.Unlit as Unlit (unlit)
 
 
@@ -23,7 +24,7 @@
       preInc = case preInclude options of
                  [] -> ""
                  is -> concatMap (\f->"#include \""++f++"\"\n") is 
-                       ++ "#line 1 \""++filename++"\"\n"
+                       ++ "#line 1 \""++cleanPath filename++"\"\n"
 
   pass1 <- cppIfdef filename (defines options) (includes options) bools
                     (preInc++input)
@@ -47,7 +48,7 @@
       preInc = case preInclude options of
                  [] -> ""
                  is -> concatMap (\f->"#include \""++f++"\"\n") is 
-                       ++ "#line 1 \""++filename++"\"\n"
+                       ++ "#line 1 \""++cleanPath filename++"\"\n"
   (pass2,syms) <-
       if macros bools then do
           pass1 <- cppIfdef filename (defines options) (includes options)
diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,5 @@
 LIBRARY = cpphs
-VERSION = 1.18.4
+VERSION = 1.18.5
 
 DIRS	= Language/Preprocessor/Cpphs \
 	  Text/ParserCombinators
@@ -32,7 +32,7 @@
 	tar cf tmp.tar $(SRCS) $(AUX)
 	mkdir $(LIBRARY)-$(VERSION)
 	cd $(LIBRARY)-$(VERSION); tar xf ../tmp.tar
-	tar zcf $(LIBRARY)-$(VERSION).tar.gz $(LIBRARY)-$(VERSION)
+	tar --format=ustar -zcf $(LIBRARY)-$(VERSION).tar.gz $(LIBRARY)-$(VERSION)
 	zip -r $(LIBRARY)-$(VERSION).zip $(LIBRARY)-$(VERSION)
 	rm -r tmp.tar $(LIBRARY)-$(VERSION)
 haddock: $(SRCS)
diff --git a/cpphs.cabal b/cpphs.cabal
--- a/cpphs.cabal
+++ b/cpphs.cabal
@@ -1,5 +1,5 @@
 Name: cpphs
-Version: 1.18.4
+Version: 1.18.5
 Copyright: 2004-2014, Malcolm Wallace
 License: LGPL
 License-File: LICENCE-LGPL
@@ -39,7 +39,7 @@
         Language.Preprocessor.Cpphs.Tokenise
 
 Executable cpphs
-    Build-Depends: base>3&&<6, old-locale, old-time, directory
+    Build-Depends: base>3&&<6, old-locale, old-time, directory, polyparse>=1.9
     Main-Is: cpphs.hs
     Other-Modules:
         Language.Preprocessor.Cpphs
diff --git a/cpphs.hs b/cpphs.hs
--- a/cpphs.hs
+++ b/cpphs.hs
@@ -20,7 +20,7 @@
 import Data.List   ( isPrefixOf )
 
 version :: String
-version = "1.18.4"
+version = "1.18.5"
 
 main :: IO ()
 main = do
diff --git a/docs/index.html b/docs/index.html
--- a/docs/index.html
+++ b/docs/index.html
@@ -198,12 +198,11 @@
 <b>Current stable version:</b>
 
 <p>
-cpphs-1.18.4, release date 2014.03.22<br>
+cpphs-1.18.5, release date 2014.06.26<br>
 By HTTP:
 <a href="http://hackage.haskell.org/package/cpphs">Hackage</a>.
 <ul>
-<li> fix the accidental flipping of comment-stripping behaviour
-     with --cpp -traditional flags.
+<li> fix a bug related to windows filepath directory separators in #includes
 </ul>
 
 <p>
@@ -225,6 +224,15 @@
 
 <p>
 <b>Older versions:</b>
+
+<p>
+cpphs-1.18.4, release date 2014.03.22<br>
+By HTTP:
+<a href="http://hackage.haskell.org/package/cpphs">Hackage</a>.
+<ul>
+<li> fix the accidental flipping of comment-stripping behaviour
+     with --cpp -traditional flags.
+</ul>
 
 <p>
 cpphs-1.18.3, release date 2014.03.03<br>
diff --git a/tests/emptyhashes b/tests/emptyhashes
deleted file mode 100644
--- a/tests/emptyhashes
+++ /dev/null
@@ -1,5 +0,0 @@
-this is a test with a hash on a line of its own
-#
-with no command after it.
-#define FOO
-and ending here
diff --git a/tests/gabor b/tests/gabor
deleted file mode 100644
--- a/tests/gabor
+++ /dev/null
@@ -1,9 +0,0 @@
-#ifndef MIN_VERSION_base
-#error "no MIN_VERSION_base"
-#endif
-
-#if MIN_VERSION_base(4, 4, 0)
-#error "4.4.0"
-#else
-#error "no 4.4.0"
-#endif
diff --git a/tests/minversion b/tests/minversion
deleted file mode 100644
--- a/tests/minversion
+++ /dev/null
@@ -1,13 +0,0 @@
-#define MIN_VERSION_base(x,y,z) (x>=4) && (y>=5) && (z>=1)
-
-#if !(MIN_VERSION_base(4, 7, 0))
-import Data.Typeable     (Typeable2, typeOf2, mkTyConApp)
-version not 4.7.0
-#endif
-#if MIN_VERSION_base(4, 4, 0)
-import Data.Typeable     (mkTyCon3)
-version 4.4.0
-#else
-import Data.Typeable     (mkTyCon)
-version any
-#endif
diff --git a/tests/runtests b/tests/runtests
--- a/tests/runtests
+++ b/tests/runtests
@@ -3,7 +3,7 @@
 FAIL=0
 
 runtest() {
-  if $1 >out 2>/dev/null && diff $2 out >/dev/null
+  if $1 >out 2>/dev/null && dos2unix -q out && diff $2 out >/dev/null
   then echo "passed: " $1
   else FAIL=$?
        echo "FAILED: ($2) " $1
diff --git a/tests/tmp b/tests/tmp
--- a/tests/tmp
+++ b/tests/tmp
@@ -1,7 +1,9 @@
-#line 1 "nomacro"
-This file is intended to show the interaction of --nomacro with --strip
-which was broken up until cpphs-1.14.
-
-Here is a line with some comment          
-Here is a line with some C89 comment               with more text after it.
-Here is a line that uses FOO but it should look like uppercase foo, not 1.
+#line 1 "booleanchain"
+
+This file tests the #if boolean expression parser/evaluator.
+
+
+
+
+SUCCEED with not and parens
+