print the search path when we can't find a module

src/GF/Compile.hs

@@ -38,6 +38,7 @@ import System.FilePath
 import System.Time
 import qualified Data.Map as Map
 import qualified Data.Set as Set
+import Data.List(nub)
 
 import PGF.Check
 import PGF.Data
@@ -108,8 +109,9 @@ compileModule opts1 env file = do
   let opts = addOptions opts0 opts1
   let fdir = dropFileName file
   let ps0 = moduleFlag optLibraryPath opts
-  ps2 <- ioeIO $ extendPathEnv $ fdir : ps0
-  let ps = ps2 ++ map (fdir </>) ps0
+  ps1 <- ioeIO $ extendPathEnv $ fdir : ps0
+  let ps2 = ps1 ++ map (fdir </>) ps0
+  ps <- ioeIO $ fmap nub $ mapM canonicalizePath ps2
   ioeIO $ putIfVerb opts $ "module search path:" +++ show ps ----
   let (_,sgr,rfs) = env
   files <- getAllFiles opts ps rfs file