[Bug lto/62249] Spurious FORTIFY_SOURCE warning with -flto, poll

[zackw at panix dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62249

--- Comment #2 from Zack Weinberg <zackw at panix dot com> ---
Incidentally, yes, the test case is based on a real program.