third_party: rapidcheck: add flag to disable rtti (#54)

We need to have an option to enable or disable rtti in rapidcheck based
on how we've configured our own build.

Most of the time we build with `-fno-rtti`.

Mixing the two leads to awful and hard to diagnose build errors.

Author: jungleraptor

third_party/rapidcheck.BUILD

@@ -8,14 +8,32 @@
 # EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
 # WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
 
+load("@bazel_skylib//rules:common_settings.bzl", "bool_flag")
+
 package(
     default_visibility = ["//visibility:public"],
 )
 
+bool_flag(
+    name = "disable_rtti",
+    build_setting_default = False,
+    visibility = ["//visibility:public"],
+)
+
+config_setting(
+    name = "_disable_rtti",
+    flag_values = {":disable_rtti": "true"},
+    visibility = ["//visibility:public"],
+)
+
 cc_library(
     name = "rapidcheck",
     srcs = glob(["src/**"]),
     hdrs = glob(["include/**"] + ["extras/**"]),
+    defines = select({
+        ":_disable_rtti": ["RC_DONT_USE_RTTI"],
+        "//conditions:default": [],
+    }),
     includes = [
         "extras/gtest/include",
         "include",