test/run_tests: Always set paths when OPENSSL_ROOT_DIR is defined

That will add the pkg-config on FreeBSD

When the environment variable OPENSSL_ROOT_DIR is defined, we need to
ensure that PATH and LD_LIBRARY_PATH are properly affected.

This is a little bit complicated, since OPENSSL_ROOT_DIR could point
at an OpenSSL build directory as well as an OpenSSL installation
tree.  Fortunately, it's easy to detect the difference; if it's a
build tree, there's a sub-directory 'apps'.

For installation trees, it's further complicated by OpenSSL's
'multilib' target attribute, which exists for platforms that support
directory separated libraries for differing bitness (typically 32-bit
and 64-bit libraries).  We trust pkg-config to give us the answer.
Binaries are easier, they live in $OPENSL_ROOT_DIR/bin.

Fixes #146

gost_pmeth.c: mitigate for constness difference in copy function

The second argument for the pkey_copy function has been constified in
OpenSSL to be 3.0.  This is normally not a problem, but when passing a
pointer to such a function, the compiler does complain.

This change solves the issue by looking at the macros
OPENSSL_VERSION_MAJOR, which is new in OpenSSL to be 3.0, and set
constness based on that.

Fixes #154

travis-ci: add linux-ppc64le build

Fix test_grasshopper and test_keyexpimp engine init

Try this approach:
https://stackoverflow.com/questions/32358197/travis-ci-install-perl-module-with-non-perl-language

Make proper engine initialization for tests instead of
EVP_add_cipher/EVP_add_digest hack. Fixes #151.

travis-ci: cleanup "so/dylib" mangling, not needed

after https://github.com/openssl/openssl/pull/8951

travis-ci: add osx builds

Fix MacOS building (master branch)

Fixes #122

Не учитывается значение carry

initial cirrus-ci support

test_tls: use socketpair instead of network connection

May fix build on Cirrus-CI, issue #134.

Fix compilation on FreeBSD

Otherwise `struct sockaddr_in` is undefined for test_tls.

Reported in #123 by f-andrey.

test_digest and alignment fix for Streebog

Some architectures in some circumstances do not allow unaligned
memory access (such as ARM, MIPS) triggering SIGBUS. This patch
very crudely fixes this issue.

The issue is found and original fix is proposed by Eric Biggers:

  https://patchwork.kernel.org/patch/10878865/

Especially test alginment problems on MIPSel.

travis-ci: switch to xenial

test_tls: simple TLS connection testing