Properly link flecs library

engine/libs/flecs/examples/c/relationships/exclusive_relations/src/main.c

@@ -0,0 +1,47 @@
+#include <exclusive_relations.h>
+#include <stdio.h>
+
+int main(int argc, char *argv[]) {
+    ecs_world_t *ecs = ecs_init_w_args(argc, argv);
+
+    ECS_TAG(ecs, Platoon);
+
+    // Register Platoon as exclusive relationship. This ensures that an entity
+    // can only belong to a single Platoon.
+    ecs_add_id(ecs, Platoon, EcsExclusive);
+
+    // Create two platoons
+    ecs_entity_t platoon_1 = ecs_new_id(ecs);
+    ecs_entity_t platoon_2 = ecs_new_id(ecs);
+
+    // Create a unit
+    ecs_entity_t unit = ecs_new_id(ecs);
+
+    // Add unit to platoon 1
+    ecs_add_pair(ecs, unit, Platoon, platoon_1);
+
+    // Log platoon of unit
+    printf("Unit in platoon 1: %s\n", 
+        ecs_has_pair(ecs, unit, Platoon, platoon_1) ? "true" : "false");
+    printf("Unit in platoon 2: %s\n\n", 
+        ecs_has_pair(ecs, unit, Platoon, platoon_2) ? "true" : "false");
+
+    // Add unit to platoon 2. Because Platoon is an exclusive relationship, this
+    // both removes (Platoon, platoon_1) and adds (Platoon, platoon_2) in a
+    // single operation.
+    ecs_add_pair(ecs, unit, Platoon, platoon_2);
+
+    printf("Unit in platoon 1: %s\n", 
+        ecs_has_pair(ecs, unit, Platoon, platoon_1) ? "true" : "false");
+    printf("Unit in platoon 2: %s\n", 
+        ecs_has_pair(ecs, unit, Platoon, platoon_2) ? "true" : "false");
+
+    // Output:
+    //  Unit in platoon 1: true
+    //  Unit in platoon 2: false
+    //  
+    //  Unit in platoon 1: false
+    //  Unit in platoon 2: true
+
+    return ecs_fini(ecs);
+}