cabal can now be used to build git-annex.

This is substantially slower than using make, does not build or install
documentation, does not run the test suite, and is not particularly
recommended, but could be useful to some.

Setup.hs

@@ -0,0 +1,17 @@
+{- cabal setup file -}
+
+import Distribution.Simple
+import System.Cmd
+
+main = defaultMainWithHooks simpleUserHooks {
+	preConf = makeSources,
+	postClean = makeClean
+}
+
+makeSources _ _ = do
+	system "make sources"
+	return (Nothing, [])
+
+makeClean _ _ _ _ = do
+	system "make clean"
+	return ()