These were left over from $FreeBSD$ removal.
Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D42612
(cherry picked from commit 1ca63a8219b88b752b064d19bd3428c61dbcf1f9)
The comment in the libc/sys symbol map referenced the generated symbols
for the syscall trampolines. Such comment was out of place in the secure
symbol map so remove the stale comment and attempt to clarify the old one
to avoid risks of confusion.
Pointed out by: kib
As part of the code refactoring to support FORTIFY_SOURCE we want
a new subdirectory "secure" to keep the files related to security.
Move the stack protector functions to this new directory.
No functional change.
Differential Review: https://reviews.freebsd.org/D3333
