Properly link flecs library

engine/libs/flecs/examples/cpp/prefabs/basics/src/main.cpp

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+#include <basics.h>
+#include <iostream>
+
+// Prefabs are entities that can be used as templates for other entities. They
+// are created with a builtin Prefab tag, which by default excludes them from
+// queries and systems.
+//
+// Prefab instances are entities that have an IsA relationship to the prefab.
+// The IsA relationship causes instances to inherit the components from the 
+// prefab. By default all instances for a prefab share its components. 
+//
+// Inherited components save memory as they only need to be stored once for all
+// prefab instances. They also speed up the creation of prefabs, as inherited
+// components don't need to be copied to the instances.
+//
+// To get a private copy of a component, an instance can add it which is called 
+// an override. Overrides can be manual (by using add) or automatic (see the
+// auto_override example).
+//
+// If a prefab has children, adding the IsA relationship instantiates the prefab
+// children for the instance (see hierarchy example).
+
+struct Defense {
+    double value;
+};
+
+int main() {
+    flecs::world ecs;
+
+    // Create a SpaceShip prefab with a Defense component.
+    flecs::entity SpaceShip = ecs.prefab("SpaceShip")
+        .set<Defense>({ 50 });
+
+    // Create a prefab instance
+    flecs::entity inst = ecs.entity("my_spaceship").is_a(SpaceShip);
+
+    // Because of the IsA relationship, the instance now shares the Defense
+    // component with the prefab, and can be retrieved as a regular component:
+    const Defense *d_inst = inst.get<Defense>();
+    std::cout << "defense: " << d_inst->value << "\n";
+
+    // Because the component is shared, changing the value on the prefab will
+    // also change the value for the instance:
+    SpaceShip.set<Defense>({ 100 });
+    std::cout << "defense after set: " << d_inst->value << "\n";
+
+    // Prefab components can be iterated like regular components:
+    ecs.each([](flecs::entity e, Defense& d) {
+        std::cout << e.path() << ": " << d.value << "\n";
+    });
+
+    // Output:
+    //  defense: 50
+    //  defense after set: 100
+    //  ::my_spaceship: 100
+}