Fixed a symbol error on Linux

Author: Ayuto

Diff for: src/core/modules/engines/engines_trace_wrap.cpp

@@ -37,6 +37,8 @@
 #include "engine/IEngineTrace.h"
 #include "public/worldsize.h"
 
+BOOST_PYTHON_OPAQUE_SPECIALIZED_TYPE_ID(CBaseEntity)
+
 
 //---------------------------------------------------------------------------------
 // External variables.