remove XMPP, DBus, DesktopNotify build flags

Make these features solely dependent on the OS being built on.

This lets stack build on windows w/o XMPP, on OSX w/o DBUS,
and on Linux with everything.

git-annex.cabal

@@ -40,9 +40,6 @@ Flag WebDAV
 Flag Inotify
   Description: Enable inotify support
 
-Flag Dbus
-  Description: Enable dbus support
-
 Flag Assistant
   Description: Enable git-annex assistant and watch command
 
@@ -55,9 +52,6 @@ Flag Webapp-secure
 Flag Pairing
   Description: Enable pairing
 
-Flag XMPP
-  Description: Enable notifications using XMPP
-
 Flag DNS
   Description: Enable the haskell DNS library for DNS lookup
 
@@ -87,9 +81,6 @@ Flag Quvi
 Flag Tahoe
   Description: Enable the tahoe special remote
 
-Flag DesktopNotify
-  Description: Enable desktop environment notifications
-
 Flag TorrentParser
   Description: Use haskell torrent library to parse torrent files
 
@@ -207,14 +198,8 @@ Executable git-annex
               C-Sources: Utility/libkqueue.c
 
   if (os(linux))
-    if flag(Dbus)
-      Build-Depends: dbus (>= 0.10.7)
-      CPP-Options: -DWITH_DBUS
-  
-    if flag(DesktopNotify)
-      if flag(Dbus)
-        Build-Depends: dbus (>= 0.10.3), fdo-notify (>= 0.3)
-        CPP-Options: -DWITH_DESKTOP_NOTIFY -DWITH_DBUS_NOTIFICATIONS
+    Build-Depends: dbus (>= 0.10.7), fdo-notify (>= 0.3)
+    CPP-Options: -DWITH_DBUS -DWITH_DESKTOP_NOTIFY -DWITH_DBUS_NOTIFICATIONS
 
   if flag(Android)
     Build-Depends: data-endian
@@ -246,7 +231,7 @@ Executable git-annex
     Build-Depends: network-multicast, network-info
     CPP-Options: -DWITH_PAIRING
 
-  if flag(XMPP) && (! os(windows))
+  if (! os(windows))
     Build-Depends: network-protocol-xmpp, gnutls (>= 0.1.4), xml-types
     CPP-Options: -DWITH_XMPP
 

stack.yaml

@@ -1,31 +1,29 @@
 flags:
   git-annex:
-    concurrentoutput: false
+    concurrentoutput: true
     tahoe: true
     tdfa: true
     inotify: true
     feed: true
     webapp-secure: true
     production: true
-    ekg: false
     assistant: true
     pairing: true
     cryptonite: true
-    xmpp: true
     network-uri: true
     s3: true
-    dbus: false
     testsuite: true
     webdav: true
     torrentparser: true
-    android: false
-    androidsplice: false
     quvi: true
     dns: true
-    desktopnotify: true
     webapp: true
+    android: false
+    androidsplice: false
+    ekg: false
 packages:
 - '.'
 extra-deps:
 - Win32-extras-0.2.0.1
+- concurrent-output
 resolver: nightly-2015-12-28