A simple one:
Index: patches/patch-include_libssl_compat_h
===================================================================
RCS file: /var/cvs/ports/net/ntp/patches/patch-include_libssl_compat_h,v
retrieving revision 1.2
diff -u -p -r1.2 patch-include_libssl_compat_h
--- patches/patch-include_libssl_compat_h 27 Mar 2017 11:33:40 -0000
1.2
+++ patches/patch-include_libssl_compat_h 26 Aug 2018 10:47:47 -0000
@@ -1,6 +1,7 @@
$OpenBSD: patch-include_libssl_compat_h,v 1.2 2017/03/27 11:33:40 bluhm Exp $
---- include/libssl_compat.h.orig Thu Mar 23 19:36:53 2017
-+++ include/libssl_compat.h Thu Mar 23 19:58:13 2017
+Index: include/libssl_compat.h
+--- include/libssl_compat.h.orig
++++ include/libssl_compat.h
@@ -37,7 +37,7 @@
#endif
@@ -10,3 +11,16 @@ $OpenBSD: patch-include_libssl_compat_h,
/* ----------------------------------------------------------------- */
# include <openssl/objects.h>
+@@ -107,10 +107,12 @@ extern int sslshim_X509_get_signature_nid(const
X509 *
+
+ #define OpenSSL_version_num SSLeay
+ #define OpenSSL_version SSLeay_version
++#if !defined(LIBRESSL_VERSION_NUMBER)
+ #define X509_get0_notBefore X509_get_notBefore
+ #define X509_getm_notBefore X509_get_notBefore
+ #define X509_get0_notAfter X509_get_notAfter
+ #define X509_getm_notAfter X509_get_notAfter
++#endif
+
+ /* ----------------------------------------------------------------- */
+ #endif /* OPENSSL_VERSION_NUMBER < v1.1.0 */
