PDF: More conservative solution to #777.

Now, instead of always creating temp dirs in the home
directory on Windows, we only do it if the system tempdir
name contains tildes.  (This will be the case for longer
usernames only.)

Closes #1192.

src/Text/Pandoc/PDF.hs

@@ -50,7 +50,8 @@ import System.Environment
 import System.Exit (ExitCode (..))
 import System.FilePath
 import System.IO (stdout)
-import System.IO.Temp (withSystemTempDirectory, withTempFile)
+import System.IO.Temp (withSystemTempDirectory, withTempDirectory,
+                       withTempFile)
 #if MIN_VERSION_base(4,8,3)
 import System.IO.Error (IOError, isDoesNotExistError)
 #else
@@ -102,7 +103,15 @@ makePDF program pdfargs writer opts doc = do
     baseProg -> do
       commonState <- getCommonState
       verbosity <- getVerbosity
-      liftIO $ withSystemTempDirectory "tex2pdf." $ \tmpdir -> do
+      -- latex has trouble with tildes in paths, which
+      -- you find in Windows temp dir paths with longer
+      -- user names (see #777)
+      let withTempDir templ action = do
+            tmp <- getTemporaryDirectory
+            if '~' `elem` tmp
+                   then withTempDirectory "." templ action
+                   else withSystemTempDirectory templ action
+      liftIO $ withTempDir "tex2pdf." $ \tmpdir -> do
         source <- runIOorExplode $ do
                     putCommonState commonState
                     doc' <- handleImages tmpdir doc