Added stack.yaml to support easy builds from source with stack.

Update install instructions.

Note that xmpp is disabled in the stack.yaml, because that needs C
libraries that would take extra work for the user to install.
xmpp is moving toward deprecation anyway.

debian/changelog

@@ -14,6 +14,7 @@ git-annex (5.20150917) UNRELEASED; urgency=medium
     yet. Triggered by eg, git-annex sync --no-commit in a fresh clone of
     a repository.
   * status: Show added but not yet committed files.
+  * Added stack.yaml to support easy builds from source with stack.
 
  -- Joey Hess <id@joeyh.name>  Wed, 16 Sep 2015 12:23:33 -0400
 

doc/install/fromsource.mdwn

@@ -34,7 +34,28 @@ First, install everything git-annex needs to build:
 Now you can build git-annex by running either `make` or `cabal build`
 inside the source tree.
 
-## minimal build with cabal and stackage
+## building from source with stack
+
+Using stack automates nearly everything, will work on many systems,
+and avoids build failures due to fast-changing haskell libraries.
+
+First, [install stack](https://github.com/commercialhaskell/stack/blob/master/doc/install_and_upgrade.md)
+It will be part of the Haskell Platform soon. On Debian unstable/testing:
+
+	sudo apt-get install haskell-stack
+
+Use stack to install all dependencies and git-annex:
+
+	stack setup
+	stack install git-annex
+
+Move git-annex into some directory that is in your PATH:
+
+	mv ~/.local/bin/git-annex ~/bin # or /usr/local/bin/ or whatever
+
+Note that this build produces a git-annex without XMPP support.
+
+## minimal build from source with cabal
 
 This can be done anywhere, and builds git-annex without some optional features
 that require harder-to-install C libraries. This is plenty to let you get started with
@@ -42,9 +63,7 @@ git-annex, but it does not include the assistant or webapp.
 
 Be warned that this involves building a lot of Haskell libraries from
 source, and so it has a lot of moving parts, and it's not uncommon for it
-to be broken from time to time. A nice way to avoid such breakage is to
-[configure cabal to use the Stackage repository](http://www.stackage.org/),
-which is a more stable and consistent version of the Hackage repository.
+to be broken from time to time.
 
 Inside the source tree, run:
 
@@ -54,15 +73,13 @@ Inside the source tree, run:
 	PATH=$HOME/bin:$PATH
 	cabal install --bindir=$HOME/bin
 
-## full build with cabal and stackage
+## full build from source with cabal
 
 To build with all features enabled, including the assistant and webapp,
 you will need to install several C libraries and their headers,
 including libgnutls, libgsasl, libxml2, and zlib. How to do that for
 your OS is beyond the scope of this page. 
 
-Using [Stackage](http://www.stackage.org/) is again a good idea here!
-
 Once the C libraries are installed, run inside the source tree:
 
 	cabal install -j --only-dependencies

stack.yaml

@@ -0,0 +1,30 @@
+flags:
+  git-annex:
+    asciiprogress: false
+    tahoe: true
+    tdfa: true
+    inotify: true
+    feed: true
+    database: true
+    webapp-secure: true
+    production: true
+    ekg: false
+    assistant: true
+    pairing: true
+    cryptonite: true
+    xmpp: false
+    network-uri: true
+    s3: true
+    dbus: true
+    testsuite: true
+    webdav: true
+    torrentparser: true
+    android: false
+    androidsplice: false
+    quvi: true
+    dns: true
+    desktopnotify: true
+    webapp: true
+packages:
+- '.'
+extra-deps: []