This change adds CRYPTO_memcmp, which compares two vectors of bytes in
an amount of time that's independent of their contents. It also changes
several MAC compares in the code to use this over the standard memcmp,
which may leak information about the size of a matching prefix.
(cherry picked from commit 2ee79888)

Conflicts:
	crypto/crypto.h
	ssl/t1_lib.c

Add additional check to catch this in ASN1_item_verify too.

PR: 2963 and a number of others

Submitted by: Dmitry Belyavsky, Seguei Leontiev
PR: 2821

Reported by: Daniel Black <daniel.black@openquery.com>

Support renewing session tickets (backport from HEAD).

Use -1 to check all extensions in CRLs.
Always set flag for freshest CRL.

Submitted by: jean-etienne.schwartz@bull.net

In OCSP_basic_varify return an error if X509_STORE_CTX_init fails.

Submitted by: Dmitry Belyavsky <beldmit@gmail.com>

Fix DH double free if parameter generation fails.

Submitted by: "Florian Rüchel" <florian.ruechel@ruhr-uni-bochum.de>

Correctly handle local machine keys in the capi ENGINE.

PR: 2896

Submitted by: Adam Langley

little maze of #ifs, all different).

Submitted by: Adam Langley

  debugging code that's seldom used.

Submitted by: Chromium Authors

Multiple copies of the ENGINE will cause problems when it is cleaned up as
the methods are stored in static structures which will be overwritten and
freed up more than once.

Set static methods to NULL when the ENGINE is freed so it can be reloaded.

[from HEAD].

PR: 2858

[from HEAD].

PR: 2838

on path with spaces [from HEAD].

PR: 2835