engine: host: add a cvar that indicates whether engine was built with…

… --enable-hl25-extended-structs or not

engine/common/host.c

@@ -1236,6 +1236,14 @@ int EXPORT Host_Main( int argc, char **argv, const char *progname, int bChangeGa
 	Cvar_Getf( "host_ver", FCVAR_READ_ONLY, "detailed info about this build", "%i " XASH_VERSION " %s %s %s", Q_buildnum(), Q_buildos(), Q_buildarch(), g_buildcommit);
 	Cvar_Getf( "host_lowmemorymode", FCVAR_READ_ONLY, "indicates if engine compiled for low RAM consumption (0 - normal, 1 - low engine limits, 2 - low protocol limits)", "%i", XASH_LOW_MEMORY );
 
+	Cvar_Get( "host_hl25_extended_structs",
+#ifdef SUPPORT_HL25_EXTENDED_STRUCTS
+		"1",
+#else
+		"0",
+#endif
+		FCVAR_READ_ONLY, "indicates if engine was compiled with extended msurface_t struct" );
+
 	Mod_Init();
 	NET_Init();
 	NET_InitMasters();