cdefs.h: add artificial attribute to FORTIFY_SOURCE functions

Otherwise the gcc compiler warning doesn't show up.

Add -Wno-error to fortify related tests. Fortify related tests
are expected to be examples of bad programs, and in many
cases shouldn't compile cleanly. Rewriting them to compile
cleanly isn't feasible nor desirable.

Bug: 17784968

(cherry picked from commit 1aaa17802c92d99ae170245c2b2f15a6c27b133e)

Change-Id: Ib6df1a3f44b55b1fff222e78395c10c51cd39817
2 files changed