buildkite: Build stack 2.1.3 via stack2nix.

Update static-stack Hackage snapshot to get the packages it needs.

Author: nh2

.buildkite/pipeline.yml

@@ -51,3 +51,12 @@ steps:
     command: |
       NIX_PATH=nixpkgs=nixpkgs nix-build --no-link survey/default.nix \
         --argstr compiler ghc865 -A workingStackageExecutables
+
+  # Stack via stack2nix
+
+  - label: static-stack
+    command: |
+      cd static-stack/
+      mkdir -p static-stack-test-dir
+      curl -L https://github.com/commercialhaskell/stack/archive/v2.1.3.tar.gz | tar -xz -C static-stack-test-dir
+      $(nix-build --no-link -A fullBuildScript --argstr stackDir $PWD/static-stack-test-dir/stack-*)

static-stack/default.nix

@@ -16,7 +16,7 @@ let
   stack2nix-script = import ../static-stack2nix-builder/stack2nix-script.nix {
     pkgs = pkgs;
     stack-project-dir = stackDir; # where stack.yaml is
-    hackageSnapshot = "2019-05-08T00:00:00Z"; # pins e.g. extra-deps without hashes or revisions
+    hackageSnapshot = "2019-08-17T00:00:00Z"; # pins e.g. extra-deps without hashes or revisions
   };
 
   static-stack2nix-builder = import ../static-stack2nix-builder/default.nix {