ledger3: Update to 3.1

This commit also adds pkgs.ledger2 and pkgs.ledger3 plus a default
attribute pkgs.ledger pointing at ledger3.

pkgs/applications/office/ledger/default.nix

@@ -0,0 +1,45 @@
+{ stdenv, fetchgit, cmake, boost, gmp, mpfr, libedit, python
+, texinfo, gnused }:
+
+let
+  version = "3.1";
+in
+
+stdenv.mkDerivation {
+  name = "ledger-${version}";
+
+  # NOTE: fetchgit because ledger has submodules not included in the
+  # default github tarball.
+  src = fetchgit {
+    url = "https://github.com/ledger/ledger.git";
+    rev = "refs/tags/v${version}";
+    sha256 = "1l5y4k830jyw7n1nnhssci3qahq091fj5cxcr77znk20nclz851s";
+  };
+
+  buildInputs = [ cmake boost gmp mpfr libedit python texinfo gnused ];
+
+  enableParallelBuilding = true;
+
+  # Skip byte-compiling of emacs-lisp files because this is currently
+  # broken in ledger...
+  postInstall = ''
+    mkdir -p $out/share/emacs/site-lisp/
+    cp -v "$src/lisp/"*.el $out/share/emacs/site-lisp/
+  '';
+
+  meta = {
+    homepage = "http://ledger-cli.org/";
+    description = "A double-entry accounting system with a command-line reporting interface";
+    license = "BSD";
+
+    longDescription = ''
+      Ledger is a powerful, double-entry accounting system that is accessed
+      from the UNIX command-line. This may put off some users, as there is
+      no flashy UI, but for those who want unparalleled reporting access to
+      their data, there really is no alternative.
+    '';
+
+    platforms = stdenv.lib.platforms.all;
+    maintainers = with stdenv.lib.maintainers; [ simons the-kenny jwiegley ];
+  };
+}