openssl: add feature check for MBEDTLS_SSL_ALPN

Fixes https://github.com/espressif/esp-idf/issues/1342

diff --git a/components/openssl/platform/ssl_pm.c b/components/openssl/platform/ssl_pm.c
index 5545f958e41589cc9b19691342f7c0648dc551c3..cd9960da12991b0c3fc25d18c37a495257a01289 100755 (executable)
--- a/components/openssl/platform/ssl_pm.c
+++ b/components/openssl/platform/ssl_pm.c
@@ -154,7 +154,11 @@ int ssl_pm_new(SSL *ssl)
     }
 
     if (ssl->ctx->ssl_alpn.alpn_status == ALPN_ENABLE) {
-        mbedtls_ssl_conf_alpn_protocols( &ssl_pm->conf, ssl->ctx->ssl_alpn.alpn_list );
+#ifdef MBEDTLS_SSL_ALPN
+        mbedtls_ssl_conf_alpn_protocols( &ssl_pm->conf, ssl->ctx->ssl_alpn.alpn_list );
+#else
+        SSL_DEBUG(SSL_PLATFORM_ERROR_LEVEL, "CONFIG_MBEDTLS_SSL_ALPN must be enabled to use ALPN", -1);
+#endif // MBEDTLS_SSL_ALPN
     }
     mbedtls_ssl_conf_rng(&ssl_pm->conf, mbedtls_ctr_drbg_random, &ssl_pm->ctr_drbg);