[ping][PATCH][BZ #13862] Reuse of cached stack can cause bounds overrun of thread DTV

[Roland McGrath]

> Please put the preprocessor condition around the whole first arm of the
> condition statement.

No, that is an anti-style.  Whenever code can be in 'if (0)' (after
constant folding) rather than in #if, that is preferable.  It makes
sure the code stays compilable even if one is only compiling one of
the configurations.