Use forward declaration header in object.hpp

include/cpptrace/forward.hpp

@@ -13,6 +13,7 @@ namespace cpptrace {
 
     struct object_frame;
     struct stacktrace_frame;
+    struct safe_object_frame;
 }
 
 #endif

src/binary/object.hpp

@@ -1,16 +1,13 @@
 #ifndef OBJECT_HPP
 #define OBJECT_HPP
 
+#include <cpptrace/forward.hpp>
+
 #include <vector>
 #include <cstdint>
 
 namespace cpptrace {
 
-struct object_frame;
-struct safe_object_frame;
-
-using frame_ptr = std::uintptr_t;
-
 namespace detail {
     object_frame get_frame_object_info(frame_ptr address);