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

third_party/bazel/rules_haskell/tests/c2hs/BUILD.bazel

@@ -0,0 +1,36 @@
+load("@io_tweag_rules_haskell//haskell:c2hs.bzl", "c2hs_library")
+load(
+    "@io_tweag_rules_haskell//haskell:haskell.bzl",
+    "haskell_library",
+)
+
+package(default_testonly = 1)
+
+c2hs_library(
+    name = "foo",
+    srcs = ["src/Foo/Foo.chs"],
+    src_strip_prefix = "src",
+    tags = [
+        "requires_c2hs",
+        "requires_zlib",
+    ],
+    deps = ["@zlib.dev//:zlib"],
+)
+
+c2hs_library(
+    name = "bar",
+    srcs = ["Bar.chs"],
+    tags = ["requires_c2hs"],
+    deps = [":foo"],
+)
+
+haskell_library(
+    name = "c2hs",
+    srcs = [
+        ":bar",
+        ":foo",
+        "@c2hs_repo//:baz",
+    ],
+    tags = ["requires_c2hs"],
+    deps = ["//tests/hackage:base"],
+)

third_party/bazel/rules_haskell/tests/c2hs/Bar.chs

@@ -0,0 +1,6 @@
+module Bar (bar) where
+
+{#import Foo.Foo#}
+
+bar :: Int
+bar = 6

third_party/bazel/rules_haskell/tests/c2hs/repo/BUILD.bazel

@@ -0,0 +1,10 @@
+load("@io_tweag_rules_haskell//haskell:c2hs.bzl", "c2hs_library")
+
+package(default_testonly = 1)
+
+c2hs_library(
+    name = "baz",
+    srcs = ["Baz.chs"],
+    visibility = ["//visibility:public"],
+    deps = ["@zlib.dev//:zlib"],
+)

third_party/bazel/rules_haskell/tests/c2hs/repo/Baz.chs

@@ -0,0 +1,6 @@
+module Baz (baz) where
+
+#include <zlib.h>
+
+baz :: Int
+baz = {# sizeof gz_header_s #}

third_party/bazel/rules_haskell/tests/c2hs/repo/WORKSPACE

@@ -0,0 +1 @@
+workspace(name = "c2hs_repo")

third_party/bazel/rules_haskell/tests/c2hs/src/Foo/Foo.chs

@@ -0,0 +1,6 @@
+module Foo.Foo (foo) where
+
+#include <zlib.h>
+
+foo :: Int
+foo = {# sizeof gz_header_s #}