Move dead submodules in-tree

Signed-off-by: swurl <swurl@swurl.xyz>

externals/oaknut/tests/rand_int.hpp

@@ -0,0 +1,20 @@
+// SPDX-FileCopyrightText: Copyright (c) 2022 merryhime <https://mary.rs>
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <random>
+#include <type_traits>
+
+template<typename T>
+T RandInt(T min, T max)
+{
+    static_assert(std::is_integral_v<T>, "T must be an integral type.");
+    static_assert(!std::is_same_v<T, signed char> && !std::is_same_v<T, unsigned char>,
+                  "Using char with uniform_int_distribution is undefined behavior.");
+
+    static std::random_device rd;
+    static std::mt19937 mt(rd());
+    std::uniform_int_distribution<T> rand(min, max);
+    return rand(mt);
+}