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

third_party/bazel/rules_haskell/tools/runfiles/test/Test.hs

@@ -0,0 +1,13 @@
+module Main (main) where
+
+import qualified Bazel.Runfiles as Runfiles
+import Control.Monad (when)
+import System.Process (callProcess)
+
+main :: IO ()
+main = do
+    r <- Runfiles.create
+    foo <- readFile (Runfiles.rlocation r "io_tweag_rules_haskell/tools/runfiles/test-data.txt")
+    when (lines foo /= ["foo"]) -- ignore trailing newline
+        $ error $ "Incorrect contents: got: " ++ show foo
+    callProcess (Runfiles.rlocation r "io_tweag_rules_haskell/tools/runfiles/bin") []