We brought an original __COUNTER__ implementation in r228474, however, it
was missing documentation and it had a different behaviour for precompiled
headers with respect to the upstream version. Since the upstream version
is under the same license as GCC4.2, bring the missing pieces to reduce
differences against upstream.
Optained from: GCC pre-4.3 (rev. 125041 ; GPLv2)
This includes additional functions to be protected: those that
have local array definitions, or have references to local frame
addresses. This is a new option in GCC-4.9 that was relicensed
by Han Shen from Google under GPLv2 for OpenBSD.
Obtained from: OpenBSD (2014-01-14)
MFC after: 2 weeks
