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.

Also, allow verbose connect setting VERBOSE=1 env var.

All tabs replcaded with spaces. One file was 2 tabs fornating.

After registration rework many callbacks not need to be exported. Also,
some functions inconsistently declared static in headers and non-static
in the code. Finally, some functions just not need to be exported.