Properly link flecs library

engine/libs/flecs/test/custom_builds/cpp/module/src/main.cpp

@@ -0,0 +1,14 @@
+#include <module.h>
+#include <iostream>
+
+struct my_module {
+    my_module(flecs::world& world) {
+        world.module<my_module>();
+    }
+};
+
+int main(int argc, char *argv[]) {
+    flecs::world world(argc, argv);
+    
+    world.import<my_module>();
+}