Properly link flecs library

engine/libs/flecs/examples/cpp/queries/without/src/main.cpp

@@ -0,0 +1,46 @@
+#include <without.h>
+#include <iostream>
+
+struct Position { 
+    double x, y;
+};
+
+struct Npc { };
+
+int main(int, char *[]) {
+    flecs::world ecs;
+
+    // Create a query for Position, !Npc. By adding the Npc component using the
+    // "without" method, the component is not a part of the query type, and as a
+    // result does not become part of the function signatures of each and iter.
+    // This is useful for things like tags, which because they don't have a 
+    // value are less useful to pass to the each/iter functions as argument.
+    //
+    // The without method is short for:
+    //   .term<Npc>().not_()
+    flecs::query<Position> q = ecs.query_builder<Position>()
+        .without<Npc>()
+        .build();
+
+    // Create a few test entities for the Position query
+    ecs.entity("e1")
+        .set<Position>({10, 20});
+
+    ecs.entity("e2")
+        .set<Position>({10, 20});
+
+    // This entity will not match as it has Npc
+    ecs.entity("e3")
+        .set<Position>({10, 20})
+        .add<Npc>();
+
+
+    // Note how the Npc tag is not part of the each signature
+    q.each([](flecs::entity e, Position& p) {
+        std::cout << e.name() << ": {" << p.x << ", " << p.y << "}\n";
+    });
+
+    // Output:
+    //  e1: {10, 20}
+    //  e2: {10, 20}
+}