[SBI] Guard OpenSSL keylog callback with version check

Wrap SSL_CTX_set_keylog_callback calls with an OpenSSL version check
to ensure compatibility with versions older than 1.1.1.

This prevents compilation issues on earlier OpenSSL releases,
such as those found on Ubuntu 18.04(bionic).

lib/sbi/client.c

@@ -386,8 +386,10 @@ static CURLcode sslctx_callback(CURL *curl, void *sslctx, void *userdata)
     /* Ensure app data is set for SSL objects */
     SSL_CTX_set_app_data(ctx, client->sslkeylog);
 
+#if OPENSSL_VERSION_NUMBER >= 0x10101000L
     /* Set the SSL Key Log callback */
     SSL_CTX_set_keylog_callback(ctx, ogs_sbi_keylog_callback);
+#endif
 
     return CURLE_OK;
 }

lib/sbi/nghttp2-server.c

@@ -216,8 +216,10 @@ static SSL_CTX *create_ssl_ctx(
     if (sslkeylog_file) {
         /* Ensure app data is set for SSL objects */
         SSL_CTX_set_app_data(ssl_ctx, sslkeylog_file);
+#if OPENSSL_VERSION_NUMBER >= 0x10101000L
         /* Set the SSL Key Log callback */
         SSL_CTX_set_keylog_callback(ssl_ctx, ogs_sbi_keylog_callback);
+#endif
     }
 
     ssl_opts = (SSL_OP_ALL & ~SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS) |