Add empty placeholders to fix HIO funcs missing when linking debug version

src/d/actor/d_a_npc_km1.cpp

@@ -32,7 +32,7 @@ public:
     daNpc_Km1_HIO_c();
     virtual ~daNpc_Km1_HIO_c() {};
 
-    void genMessage(JORMContext* ctx);
+    void genMessage(JORMContext* ctx) {}
 
 public:
     /* 0x04 */ s8 mNo;