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

third_party/bazel/rules_haskell/tests/textual-hdrs/BUILD.bazel

@@ -0,0 +1,17 @@
+load(
+    "@io_tweag_rules_haskell//haskell:haskell.bzl",
+    "haskell_test",
+)
+
+package(default_testonly = 1)
+
+haskell_test(
+    name = "textual-hdrs",
+    srcs = [
+        "Main.hs",
+        "include/main_definition.h",
+    ],
+    compiler_flags = ["-Itests/textual-hdrs/include"],
+    visibility = ["//visibility:public"],
+    deps = ["//tests/hackage:base"],
+)

third_party/bazel/rules_haskell/tests/textual-hdrs/Main.hs

@@ -0,0 +1,5 @@
+{-# LANGUAGE CPP #-}
+
+module Main (main) where
+
+#include "main_definition.h"

third_party/bazel/rules_haskell/tests/textual-hdrs/include/main_definition.h

@@ -0,0 +1,2 @@
+main :: IO ()
+main = putStrLn "extras-included-during-comp"