feat(third_party/bazel): Check in rules_haskell from Tweag

third_party/bazel/rules_haskell/shell.nix

@@ -0,0 +1,51 @@
+{ pkgs ? import ./nixpkgs {}, docTools ? true }:
+
+with pkgs;
+
+mkShell {
+  # XXX: hack for macosX, this flags disable bazel usage of xcode
+  # Note: this is set even for linux so any regression introduced by this flag
+  # will be catched earlier
+  # See: https://github.com/bazelbuild/bazel/issues/4231
+  BAZEL_USE_CPP_ONLY_TOOLCHAIN=1;
+
+  buildInputs = [
+    go
+    nix
+    which
+    perl
+    python
+    bazel
+    # Needed for @com_github_golang_protobuf, itself needed by buildifier.
+    git
+    # Needed to get correct locale for tests with encoding
+    glibcLocales
+    # to check haddock outputs
+    linkchecker
+    # to avoid CA certificate failures on MacOS CI
+    cacert
+    # Needed for debug/linking_utils
+    binutils
+  ] ++ lib.optionals docTools [graphviz python36Packages.sphinx zip unzip];
+
+  shellHook = ''
+    # Add nix config flags to .bazelrc.local.
+    #
+    BAZELRC_LOCAL=".bazelrc.local"
+    if [ ! -e "$BAZELRC_LOCAL" ]
+    then
+      ARCH=""
+      if [ "$(uname)" == "Darwin" ]; then
+        ARCH="darwin"
+      elif [ "$(expr substr $(uname -s) 1 5)" == "Linux" ]; then
+        ARCH="linux"
+      fi
+      echo "[!] It looks like you are using a ''${ARCH} nix-based system. In order to build this project, you probably need to add the two following host_platform entries to your .bazelrc.local file."
+      echo ""
+      echo "test --host_platform=@io_tweag_rules_haskell//haskell/platforms:''${ARCH}_x86_64_nixpkgs"
+    fi
+
+    # source bazel bash completion
+    source ${pkgs.bazel}/share/bash-completion/completions/bazel
+  '';
+}