add build flags to version output

BuildFlags.hs

@@ -0,0 +1,51 @@
+{- git-annex build flags reporting
+ -
+ - Copyright 2013 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+{-# LANGUAGE CPP #-}
+
+module BuildFlags where
+
+buildFlags :: [String]
+buildFlags = filter (not . null)
+	[ ""
+#ifdef WITH_ASSISTANT
+	, "Assistant"
+#endif
+#ifdef WITH_WEBAPP
+	, "Webapp"
+#endif
+#ifdef WITH_PAIRING
+	, "Pairing"
+#endif
+#ifdef WITH_TESTSUITE
+	, "Testsuite"
+#endif
+#ifdef WITH_S3
+	, "S3"
+#endif
+#ifdef WITH_WEBDAV
+	, "WebDAV"
+#endif
+#ifdef WITH_INOTIFY
+	, "Inotify"
+#endif
+#ifdef WITH_FSEVENTS
+	, "FsEvents"
+#endif
+#ifdef WITH_KQUEUE
+	, "Kqueue"
+#endif
+#ifdef WITH_DBUS
+	, "DBus"
+#endif
+#ifdef WITH_XMPP
+	, "XMPP"
+#endif
+#ifdef WITH_DNS
+	, "DNS"
+#endif
+	]