--- libESMTP-1.1.0.orig/smtp-tls.c	2021-06-04 18:18:50.000000000 +0200
+++ libESMTP-1.1.0/smtp-tls.c	2026-05-19 21:31:51.235036745 +0200
@@ -20,6 +20,7 @@
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
+#define _BSD_SOURCE
 #include <config.h>
 
 /* Support for the SMTP STARTTLS verb.
