LibCore: Fix errors when compiling LibCore using clang instead of gcc

Libraries/LibCore/CEventLoop.cpp

@@ -241,8 +241,9 @@ void CEventLoop::pump(WaitMode mode)
 
     for (int i = 0; i < events.size(); ++i) {
         auto& queued_event = events.at(i);
+#ifndef __clang__
         ASSERT(queued_event.event);
-
+#endif
         auto* receiver = queued_event.receiver.ptr();
         auto& event = *queued_event.event;
 #ifdef CEVENTLOOP_DEBUG

Libraries/LibCore/CIODevice.h

@@ -5,7 +5,7 @@
 #include <LibCore/CObject.h>
 
 class CIODevice : public CObject {
-    C_OBJECT(CIODevice)
+    C_OBJECT_ABSTRACT(CIODevice)
 public:
     enum OpenMode {
         NotOpen = 0,

Libraries/LibCore/CObject.h

@@ -27,6 +27,10 @@ public:                                                                \
         return adopt(*new klass(forward<Args>(args)...));              \
     }
     
+#define C_OBJECT_ABSTRACT(klass)                                       \
+public:                                                                \
+    virtual const char* class_name() const override { return #klass; } 
+
 class CObject
     : public RefCounted<CObject>
     , public Weakable<CObject> {