[CodeGen] Generate goldsrc engine defination.

[anchurcn]

Problems

1. The struct with direct function pointer declaration field yields empty struct in AstCpp compilation. eg:

   typedef struct r_studio_interface_s
   {
   int version;
   int (*StudioDrawModel)(int flags);
   int (*StudioDrawPlayer)(int flags, struct entity_state_s* pplayer);
   } r_studio_interface_t;

   yields empty struct (ast representation): struct r_studio_interface_s{ }

2. The struct with typedef function pointer declaration field yields zero parameter function type of the fields. eg:

   // Pointers to the exported engine functions themselves
   typedef struct cl_enginefuncs_s
   {
   pfnEngSrc_pfnSPR_Load_t pfnSPR_Load;
   pfnEngSrc_pfnSPR_Frames_t pfnSPR_Frames;
   pfnEngSrc_pfnSPR_Height_t pfnSPR_Height;
   pfnEngSrc_pfnSPR_Width_t pfnSPR_Width;
      //...
   }

   yields struct cl_enginefuncs_s{ void(*)() pfnSPR_Load; ... } but actual type of pfnSPR_Load is typedef HSPRITE (*pfnEngSrc_pfnSPR_Load_t)(const char* szPicName);