engine: add stub function for new undocumented function in clientdll api

engine/cdll_int.h

@@ -303,6 +303,9 @@ typedef struct cl_enginefuncs_s
 	int		(*pfnGetAppID)( void );
 	cmdalias_t	*(*pfnGetAliases)( void );
 	void		(*pfnVguiWrap2_GetMouseDelta)( int *x, int *y );
+
+	// added in 2019 update, not documented yet
+	int		(*pfnFilteredClientCmd)( const char *cmd );
 } cl_enginefunc_t;
 
 #define CLDLL_INTERFACE_VERSION	7

engine/client/cl_game.c

@@ -3903,6 +3903,10 @@ static cl_enginefunc_t gEngfuncs =
 	pfnGetAppID,
 	Cmd_AliasGetList,
 	pfnVguiWrap2_GetMouseDelta,
+
+	// HACKHACK: added it here so it wouldn't cause overflow or segfault
+	// TODO: itself client command filtering is not implemented yet
+	pfnClientCmd
 };
 
 void CL_UnloadProgs( void )