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

third_party/bazel/rules_haskell/examples/rts/main.c

@@ -0,0 +1,11 @@
+#include <stdio.h>
+#include "HsFFI.h"
+
+extern HsInt add_one_hs(HsInt a0);
+
+int main(int argc, char *argv[]) {
+  hs_init(&argc, &argv);
+  printf("Adding one to 5 through Haskell is %ld\n", add_one_hs(5));
+  hs_exit();
+  return 0;
+}