tls: backends use connection filters for IO, enabling HTTPS-proxy

 - OpenSSL (and compatible)
 - BearSSL
 - gnutls
 - mbedtls
 - rustls
 - schannel
 - secure-transport
 - wolfSSL (v5.0.0 and newer)

 This leaves only the following without HTTPS-proxy support:
 - gskit
 - nss
 - wolfSSL (versions earlier than v5.0.0)

Closes #9962

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/ftp.c b/lib/ftp.c
index c07bafe17..8f0ac2e69 100644
--- a/lib/ftp.c
+++ b/lib/ftp.c
@@ -2742,7 +2742,7 @@ static CURLcode ftp_statemachine(struct Curl_easy *data,
       if((ftpcode == 234) || (ftpcode == 334)) {
         /* this was BLOCKING, keep it so for now */
         bool done;
-        if(!Curl_ssl_conn_is_ssl(data, FIRSTSOCKET)) {
+        if(!Curl_conn_is_ssl(data, FIRSTSOCKET)) {
           result = Curl_ssl_cfilter_add(data, conn, FIRSTSOCKET);
           if(result) {
             /* we failed and bail out */