Full test of OFB to match GOST R 34.13-2015 test vectors is impossible,
due to test IVs are having size (256-bits) over the maximum openssl can
allow (128-bits).

I generated new test vectors from canonical implementation
from `PR_GOSTR_bch_v9.zip` (revision of 2016-10-28) by truncating test
IVs in half.

(cherry picked from commit d40efde8)

Make sure stream modes can encrypt any block size.

(cherry picked from commit 6e163b2c)

(cherry picked from commit 370c40df)

test_grasshopper: test modes to match GOST vectors
Only ECB and CTR modes are tested. OBF, CBC, CFB modes is not testable
under openssl.

(cherry picked from commit 6547c44e)

Co-authored-by: Mikhail Gordeev <obirvalger@altlinux.org>
(cherry picked from commit 0329b9a7)

(*) convert 'openssl ciphers | grep ...' into Test:More syntax

(cherry picked from commit abf1f767)

(cherry picked from commit 1d378c56)

(cherry picked from commit 6eb11c67)

(cherry picked from commit 3461793c)

Backport grasshopper-ctr and grasshopper-ofb fixes to 1.1.0 branch

Also, document why CTR IV size is now set to 16, so user is noted to set
IV appropriately to full extent (including counter). Basically, it's for
openssh (and alike) to make it copy IV from privilege separated process.

(cherry picked from commit 74d13288)

Previous implementation was not OFB at all, and fail tests.

Note: This implementation is for fixed width 128-bit IV which makes
shift regiser redundant.

(cherry picked from commit 1e15537d)

Previously CTR did not continue unfinished block on the next cipher
iteration.

(cherry picked from commit cf2ab51a)

(cherry picked from commit 6be1ab00)

Address compiler warnings and build with CMAKE_C_FLAGS

like the README suggests.

Fix error in printf() invocation

where they reside

Make gost-engine independent of OpenSSL SOURCE

It really already was, this only removes artifacts in CMakeLists.txt

Separate GOST engine and GOST library, make GOST engine a module

The GOST engine file was "libgost_engine.so".  Unfortunately, this
will fail to load with any OpenSSL version, as the derived engine ID
will be "gost_engine" (OpenSSL <1.1.0) or "libgost_engine" (OpenSSL
>=1.1.0), since the engine checks the ID internally against "gost".

To make the IDs compatible, make sure the file name will be "gost.so"