WGL: Don't depend on Core/VideoCommon

Source/Core/VideoBackends/OGL/main.cpp

@@ -84,6 +84,12 @@ Make AA apply instantly during gameplay if possible
 namespace OGL
 {
 
+// Draw messages on top of the screen
+unsigned int VideoBackend::PeekMessages()
+{
+	return GLInterface->PeekMessages();
+}
+
 std::string VideoBackend::GetName() const
 {
 	return "OGL";