+/* If using the C implementation of alloca, define if you know the
+ direction of stack growth for your system; otherwise it will be
+ automatically deduced at run-time.
+ STACK_DIRECTION > 0 => grows toward higher addresses
+ STACK_DIRECTION < 0 => grows toward lower addresses
+ STACK_DIRECTION = 0 => direction of growth unknown */
+#undef STACK_DIRECTION