- tag more functions with gnu format attribute

- fix format string bugs. still some left

code/client/cl_cgame.c

@@ -415,10 +415,10 @@ The cgame module is making a system call
 intptr_t CL_CgameSystemCalls( intptr_t *args ) {
 	switch( args[0] ) {
 	case CG_PRINT:
-		Com_Printf( "%s", VMA(1) );
+		Com_Printf( "%s", (const char*)VMA(1) );
 		return 0;
 	case CG_ERROR:
-		Com_Error( ERR_DROP, "%s", VMA(1) );
+		Com_Error( ERR_DROP, "%s", (const char*)VMA(1) );
 		return 0;
 	case CG_MILLISECONDS:
 		return Sys_Milliseconds();