pgsql: Support OpenSSL 1.1.0 in 9.3 and 9.2.

Support OpenSSL 1.1.0 in 9.3 and 9.2.

This commit back-patches the equivalent of the 9.5-branch commits
e2838c580 and 48e5ba61e, so that we can work with OpenSSL 1.1.0
in all supported branches.

Original patches by Andreas Karlsson and Heikki Linnakangas,
back-patching work by Andreas Karlsson.

Patch: https://postgr.es/m/0c817abb-3f7d-20fb-583a-58f7593a0bea@proxel.se
Discussion: https://postgr.es/m/5129.1492293840@sss.pgh.pa.us

Branch
------
REL9_2_STABLE

Details
-------
http://git.postgresql.org/pg/commitdiff/fb50c38e9cb4f4a9953a918664536f3e344ec858

Modified Files
--------------
configure | 257 +++++++++++++++++++++++++++++++++++----
configure.in | 14 ++-
contrib/pgcrypto/internal.c | 9 --
contrib/pgcrypto/openssl.c | 130 +++++++++++++++-----
contrib/pgcrypto/pgp-s2k.c | 6 +-
contrib/pgcrypto/px-crypt.c | 2 +-
contrib/pgcrypto/px.h | 1 -
src/backend/libpq/be-secure.c | 91 +++++++++++---
src/include/pg_config.h.in | 15 +++
src/interfaces/libpq/fe-secure.c | 25 ++--
src/interfaces/libpq/libpq-int.h | 2 +-
11 files changed, 464 insertions(+), 88 deletions(-)