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.

Utility/ThreadScheduler.hs

@@ -6,13 +6,17 @@
  - Licensed under the GNU GPL version 3 or higher.
  -}
 
+{-# LANGUAGE CPP #-}
+
 module Utility.ThreadScheduler where
 
 import Common
 
 import Control.Concurrent
-import System.Posix.Terminal
 import System.Posix.Signals
+#ifndef WITH_ANDROID
+import System.Posix.Terminal
+#endif
 
 newtype Seconds = Seconds { fromSeconds :: Int }
 	deriving (Eq, Ord, Show)
@@ -49,8 +53,10 @@ waitForTermination :: IO ()
 waitForTermination = do
 	lock <- newEmptyMVar
 	check softwareTermination lock
+#ifndef WITH_ANDROID
 	whenM (queryTerminal stdInput) $
 		check keyboardSignal lock
+#endif
 	takeMVar lock
   where
 	check sig lock = void $

Utility/libdiskfree.c

@@ -22,6 +22,10 @@
 # define STATCALL statfs /* statfs64 not yet tested on a real FreeBSD machine */
 # define STATSTRUCT statfs
 #else
+#if defined WITH_ANDROID
+# warning free space checking code not available for Android
+# define UNKNOWN
+#else
 #if defined (__linux__) || defined (__FreeBSD_kernel__)
 /* Linux or Debian kFreeBSD */
 /* This is a POSIX standard, so might also work elsewhere too. */
@@ -34,6 +38,7 @@
 #endif
 #endif
 #endif
+#endif
 
 #include <errno.h>
 #include <stdio.h>

Utility/libmounts.h

@@ -5,6 +5,10 @@
 # include <sys/mount.h>
 # define GETMNTINFO
 #else
+#if defined WITH_ANDROID
+# warning mounts listing code not available for Android
+# define UNKNOWN
+#else
 #if defined (__linux__) || defined (__FreeBSD_kernel__)
 /* Linux or Debian kFreeBSD */
 #include <mntent.h>
@@ -14,6 +18,7 @@
 # define UNKNOWN
 #endif
 #endif
+#endif
 
 #include <stdio.h>