can now build Android targeted binary

Various things that don't work on Android are just ifdefed out.

* the webapp (needs template haskell for arm)
* --include and --exclude globbing (needs libpcre, which is not ported;
  probably I'll make it use the pure haskell glob library instead)
* annex.diskreserve checking (missing sys/statvfs.h)
* timestamp preservation support (yawn)
* S3
* WebDAV
* XMPP

The resulting 17mb binary has been tested on Android, and it is able to,
at least, print its usage message.

Limit.hs

@@ -5,13 +5,17 @@
  - Licensed under the GNU GPL version 3 or higher.
  -}
 
+{-# LANGUAGE CPP #-}
+
 module Limit where
 
-import Text.Regex.PCRE.Light.Char8
-import System.Path.WildMatch
 import Data.Time.Clock.POSIX
 import qualified Data.Set as S
 import qualified Data.Map as M
+#ifndef WITH_ANDROID
+import Text.Regex.PCRE.Light.Char8
+import System.Path.WildMatch
+#endif
 
 import Common.Annex
 import qualified Annex
@@ -81,11 +85,15 @@ limitExclude :: MkLimit
 limitExclude glob = Right $ const $ return . not . matchglob glob
 
 matchglob :: String -> Annex.FileInfo -> Bool
+#ifdef WITH_ANDROID
+matchglob _ _ = error "glob matching not supported"
+#else
 matchglob glob (Annex.FileInfo { Annex.matchFile = f }) =
 	isJust $ match cregex f []
   where
 	cregex = compile regex []
 	regex = '^':wildToRegex glob
+#endif
 
 {- Adds a limit to skip files not believed to be present
  - in a specfied repository. -}