Make Distribution.Compat.Char for isSymbol; fixes the build with GHC 6.4

Distribution/Compat/Char.hs

+{-# LANGUAGE CPP, ForeignFunctionInterface #-}
+{-# OPTIONS_GHC -cpp -fffi #-}
+{-# OPTIONS_NHC98 -cpp #-}
+{-# OPTIONS_JHC -fcpp #-}
+-- #hide
+module Distribution.Compat.Char (isSymbol) where
+
+import Data.Char
+#if defined(__GLASGOW_HASKELL__) && (__GLASGOW_HASKELL__ < 606)
+import Foreign.C
+
+isSymbol :: Char -> Bool
+isSymbol c = case generalCategory c of
+        MathSymbol              -> True
+        CurrencySymbol          -> True
+        ModifierSymbol          -> True
+        OtherSymbol             -> True
+        _                       -> False
+
+-- Euch euch euch: This isn't at all nice. isSymbol is actually defined in
+-- GHC.Unicode, but not exported! And nor is generalCategory.
+
+generalCategory :: Char -> GeneralCategory
+generalCategory c = toEnum (wgencat (fromIntegral (ord c)))
+
+data GeneralCategory
+        = UppercaseLetter       -- Lu  Letter, Uppercase
+        | LowercaseLetter       -- Ll  Letter, Lowercase
+        | TitlecaseLetter       -- Lt  Letter, Titlecase
+        | ModifierLetter        -- Lm  Letter, Modifier
+        | OtherLetter           -- Lo  Letter, Other
+        | NonSpacingMark        -- Mn  Mark, Non-Spacing
+        | SpacingCombiningMark  -- Mc  Mark, Spacing Combining
+        | EnclosingMark         -- Me  Mark, Enclosing
+        | DecimalNumber         -- Nd  Number, Decimal
+        | LetterNumber          -- Nl  Number, Letter
+        | OtherNumber           -- No  Number, Other
+        | ConnectorPunctuation  -- Pc  Punctuation, Connector
+        | DashPunctuation       -- Pd  Punctuation, Dash
+        | OpenPunctuation       -- Ps  Punctuation, Open
+        | ClosePunctuation      -- Pe  Punctuation, Close
+        | InitialQuote          -- Pi  Punctuation, Initial quote
+        | FinalQuote            -- Pf  Punctuation, Final quote
+        | OtherPunctuation      -- Po  Punctuation, Other
+        | MathSymbol            -- Sm  Symbol, Math
+        | CurrencySymbol        -- Sc  Symbol, Currency
+        | ModifierSymbol        -- Sk  Symbol, Modifier
+        | OtherSymbol           -- So  Symbol, Other
+        | Space                 -- Zs  Separator, Space
+        | LineSeparator         -- Zl  Separator, Line
+        | ParagraphSeparator    -- Zp  Separator, Paragraph
+        | Control               -- Cc  Other, Control
+        | Format                -- Cf  Other, Format
+        | Surrogate             -- Cs  Other, Surrogate
+        | PrivateUse            -- Co  Other, Private Use
+        | NotAssigned           -- Cn  Other, Not Assigned
+        deriving (Eq, Ord, Enum, Read, Show, Bounded)
+
+foreign import ccall unsafe "u_gencat"
+  wgencat :: CInt -> Int
+#endif
+

Distribution/ParseUtils.hs

@@ -72,7 +72,8 @@ import Distribution.Simple.Utils (intercalate, lowercase)
 import Language.Haskell.Extension (Extension)
 
 import Text.PrettyPrint.HughesPJ hiding (braces)
-import Data.Char (isSpace, isUpper, toLower, isAlphaNum, isSymbol, isDigit)
+import Data.Char (isSpace, isUpper, toLower, isAlphaNum, isDigit)
+import Distribution.Compat.Char (isSymbol)
 import Data.Maybe	(fromMaybe)
 import Data.Tree as Tree (Tree(..), flatten)
 import System.FilePath (normalise)