Note, you will need to pass `-lsocket -lnsl` to the gcc for
socketpair(3SOCKET) to link `test_tls'.

This is based on AX_CHECK_ALIGNED_ACCESS_REQUIRED from autoconf-archive.

Note, that on some arches unaligned access behavior could be changed at
runtime via prctl(1). Also, unaligned memory access is still slower (and
very slow on some arches) even if it's not strictly required.

Plus some minor style fix

ECCKiila Changes from

https://gitlab.com/nisec/ecckiila/-/issues/2

https://gitlab.com/nisec/ecckiila/-/commit/7445ecabef77965743e0ae8d39d7433b07820be6

* X3 -> X1
* eliminate a temp variable

X3 = X1 as pointers is the reason this was still passing unit tests.
But that might not hold in future versions of ECCKiila, so fix it now.

char defaults to signed on x86/x64, but unsigned on ARM.

Test all VKOs and KEGs to work and produce same keys for both parties.

Format: vko:<bit length>
Such as:
  vko:256 for VKO_256
  vko:512 for VKO_512
  vko:0   disable strict VKO mode, switch to other derive methods.

Suitable for tests. Use EVP_PKEY_CTRL_SET_VKO ctrl with appropriate
digest nid to enable VKO mode.

Standalone EC implementations from ECCKiila.

https://gitlab.com/nisec/ecckiila

* GOST key agreement cofactor fix

Bug found by Clang scan-build.

Fixes #258.

Fixes #257

openssl/openssl#11720 provided the necessary fix.

Test for conversion errors.

Such as, no need to run tests if build failed.