Fix naked pointer in cipher function

[Firgeis]

Fixes #143

[anmonteiro]

CI isn't too happy:

ssl_stubs.c: In function 'ocaml_ssl_get_current_cipher':
ssl_stubs.c:1083:43: error: invalid application of 'sizeof' to incomplete type 'SSL_CIPHER' {aka 'struct ssl_cipher_st'}
 1083 |   value vcipher = caml_alloc_small(sizeof(SSL_CIPHER), Abstract_tag);
      |                                           ^~~~~~~~~~
ssl_stubs.c:1084:47: error: lvalue required as left operand of assignment
 1084 |   *((SSL_CIPHER *) Data_abstract_val(vcipher) = cipher);
      |                                               ^

[Firgeis]

Seems to me the tests are passing but there is some issue with building the ssl dependency

[anmonteiro]

Seems to me the tests are passing but there is some issue with building the ssl dependency

I don't think so. There are 5 cipher tests, but I only see 4 in the CI output. I suspect it's segfaulting.

[Firgeis]

@anmonteiro should be good to go

[anmonteiro]

LGTM. Could you add an entry to the change log please?

[anmonteiro]

Thanks!