Just wrote my own entity system to figure it out.

rand.cpp

@@ -1,10 +1,6 @@
 #include "rand.hpp"
 
-std::random_device RNG;
-std::mt19937 GENERATOR(RNG());
-
-int Random::rand_int(int from, int to) {
-    std::uniform_int_distribution<int> rand(from, to);
-
-    return rand(GENERATOR);
+namespace Random {
+  std::random_device RNG;
+  std::mt19937 GENERATOR(RNG());
 }