Add `fetchbzr', to retrieve remote Bazaar repositories.

svn path=/nixpkgs/trunk/; revision=12924

pkgs/build-support/fetchbzr/builder.sh

@@ -0,0 +1,9 @@
+source "$stdenv/setup"
+
+header "exporting \`$url' (revision $revision) into \`$out'"
+
+# Perform a lightweight checkout so that we don't end up importing
+# all the repository's history.
+bzr checkout --lightweight "$url" -r "$revision" "$out"
+
+stopNest

pkgs/build-support/fetchbzr/default.nix

@@ -0,0 +1,15 @@
+{ stdenv, bazaar }: 
+{ url, revision, sha256 }:
+
+stdenv.mkDerivation {
+  name = "bzr-export";
+
+  builder = ./builder.sh;
+  buildInputs = [ bazaar ];
+
+  outputHashAlgo = "sha256";
+  outputHashMode = "recursive";
+  outputHash = sha256;
+  
+  inherit url revision;
+}

pkgs/top-level/all-packages.nix

@@ -353,6 +353,10 @@ let
     inherit fetchurl stdenv;
   };
 
+  fetchbzr = import ../build-support/fetchbzr {
+    inherit stdenv bazaar;
+  };
+
   fetchcvs = import ../build-support/fetchcvs {
     inherit stdenv cvs;
   };