-/* Set up ACTION so that it is invoked on C stack overflow. Return -1
- (setting errno) if this cannot be done.
-
- When ACTION is called, it is passed an argument equal to SIGSEGV
- for a segmentation violation that does not appear related to stack
- overflow, and is passed zero otherwise. On many platforms it is
- hard to tell; when in doubt, zero is passed.
-
- A null ACTION acts like an action that does nothing.
-
- ACTION must be async-signal-safe. ACTION together with its callees
- must not require more than SIGSTKSZ bytes of stack space. Also,
- ACTION should not call longjmp, because this implementation does
- not guarantee that it is safe to return to the original stack. */
-