Convert an EVP_PKEY into a PKCS#8 PrivateKeyInfo structure.
Declared in <openssl/x509.h>
<openssl/x509.h>
PKCS8_PRIV_KEY_INFO* EVP_PKEY2PKCS8(EVP_PKEY const* pkey);
Newly allocated PKCS8_PRIV_KEY_INFO, or NULL on error; free with PKCS8_PRIV_KEY_INFO_free().