diff --git a/asn1/asn1c/Makefile.am b/asn1/asn1c/Makefile.am
index 3829c5ebc..f11d0fac6 100644
--- a/asn1/asn1c/Makefile.am
+++ b/asn1/asn1c/Makefile.am
@@ -76,4 +76,5 @@ noinst_LTLIBRARIES=libasn1c.la
 
 regenerate:
 	asn1c -fskeletons-copy -fnative-types ipa.asn1
+	$(SED) -i s/_BSD_SOURCE/_DEFAULT_SOURCE/g asn_system.h
 	rm -f converter-sample.c Makefile.am.sample
diff --git a/asn1/asn1c/asn_system.h b/asn1/asn1c/asn_system.h
index d19837edf..991177797 100644
--- a/asn1/asn1c/asn_system.h
+++ b/asn1/asn1c/asn_system.h
@@ -13,8 +13,8 @@
 #include "config.h"
 #endif
 
-#ifndef _BSD_SOURCE
-#define _BSD_SOURCE /* for snprintf() on some linux systems  */
+#ifndef _DEFAULT_SOURCE
+#define _DEFAULT_SOURCE /* for snprintf() on some linux systems  */
 #endif
 
 #include <stdio.h>	/* For snprintf(3) */