libc: Purge unneeded cdefs.h

These sys/cdefs.h are not needed. Purge them. They are mostly left-over
from the $FreeBSD$ removal. A few in libc are still required for macros
that cdefs.h defines. Keep those.

Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D42385

Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

libc glob: Avoid pathological exponential behavior

Adapt glob's match() routine to use a greedy algorithm that avoids
exponential runtime in byzantine inputs.

While here, add a testcase for the byzantine input.

Prompted by: https://research.swtch.com/glob
Authored by: Yves Orton <demerphq at gmail.com>
Obtained from: Perl (33252c318625f3c6c89b816ee88481940e3e6f95)
Sponsored by: Dell EMC Isilon