Implement SSL_read_ex() and SSL_write_ex() as documented.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
GH: #1964

ssl/ssl_err.c

diff --git a/ssl/ssl_err.c b/ssl/ssl_err.c
index bcb9ddb..addc3de 100644
--- a/ssl/ssl_err.c
+++ b/ssl/ssl_err.c
@@ -203,8 +203,10 @@
      "ssl_parse_serverhello_use_srtp_ext"},
     {ERR_FUNC(SSL_F_SSL_PEEK), "SSL_peek"},
     {ERR_FUNC(SSL_F_SSL_PEEK_EX), "SSL_peek_ex"},
+    {ERR_FUNC(SSL_F_SSL_PEEK_INTERNAL), "ssl_peek_internal"},
     {ERR_FUNC(SSL_F_SSL_READ), "SSL_read"},
     {ERR_FUNC(SSL_F_SSL_READ_EX), "SSL_read_ex"},
+    {ERR_FUNC(SSL_F_SSL_READ_INTERNAL), "ssl_read_internal"},
     {ERR_FUNC(SSL_F_SSL_RENEGOTIATE), "SSL_renegotiate"},
     {ERR_FUNC(SSL_F_SSL_SCAN_CLIENTHELLO_TLSEXT),
      "ssl_scan_clienthello_tlsext"},
@@ -252,6 +254,7 @@
     {ERR_FUNC(SSL_F_SSL_VERIFY_CERT_CHAIN), "ssl_verify_cert_chain"},
     {ERR_FUNC(SSL_F_SSL_WRITE), "SSL_write"},
     {ERR_FUNC(SSL_F_SSL_WRITE_EX), "SSL_write_ex"},
+    {ERR_FUNC(SSL_F_SSL_WRITE_INTERNAL), "ssl_write_internal"},
     {ERR_FUNC(SSL_F_STATE_MACHINE), "state_machine"},
     {ERR_FUNC(SSL_F_TLS12_CHECK_PEER_SIGALG), "tls12_check_peer_sigalg"},
     {ERR_FUNC(SSL_F_TLS13_CHANGE_CIPHER_STATE), "tls13_change_cipher_state"},