Refactor macro-spanning if in ssl_tls12_client.c

Signed-off-by: David Horstmann <david.horstmann@arm.com>
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 0267af7..46ef43f 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -3451,9 +3451,11 @@
         if( ( ret = mbedtls_pk_verify_restartable( peer_pk,
                         md_alg, hash, hashlen, p, sig_len, rs_ctx ) ) != 0 )
         {
+            int send_alert_msg = 1;
 #if defined(MBEDTLS_SSL_ECP_RESTARTABLE_ENABLED)
-            if( ret != MBEDTLS_ERR_ECP_IN_PROGRESS )
+            send_alert_msg = ( ret != MBEDTLS_ERR_ECP_IN_PROGRESS );
 #endif
+            if( send_alert_msg )
                 mbedtls_ssl_send_alert_message(
                     ssl,
                     MBEDTLS_SSL_ALERT_LEVEL_FATAL,