X509_STORE_CTX_get_ex_data reads the context's ex_data stack, and
X509_STORE_CTX_get1_chain copies the chain stack and raises each
certificate's reference count. UI_set_result checks a prompt or verify
result against its bounds, queuing UI_R_RESULT_TOO_SMALL or _LARGE and
marking the UI redoable, copies it, or picks a boolean answer.
PKCS12_PBE_add, OBJ_cleanup and SSL_load_error_strings return without
an observable effect, as LibreSSL 2.5.4 does while no object is added
and no error string is read.