Add patch with upstream commit a348d830659fffd2cfc42994524783b07e69b4b5:

Don't use '\n' in sed substitution.  FreeBSD sed interprets it as a
regular 'n', not as a newline.

PR:		239285
Submitted by:	Ting-Wei Lan <lantw44@gmail.com>

devel/automake/Makefile

@@ -3,7 +3,7 @@
 
 PORTNAME=	automake
 PORTVERSION=	1.16.1
-PORTREVISION=	1
+PORTREVISION=	2
 CATEGORIES=	devel
 MASTER_SITES=	GNU
 

devel/automake/files/patch-bug31222

@@ -0,0 +1,31 @@
+From a348d830659fffd2cfc42994524783b07e69b4b5 Mon Sep 17 00:00:00 2001
+From: Mathieu Lirzin <mthl@gnu.org>
+Date: Sun, 8 Jul 2018 23:41:42 +0200
+Subject: [PATCH] python: Don't use '\n' in sed substitution
+
+This change fixes automake bug#31222.
+
+On macOS, 'sed' interprets '\n' in the substitution text as the letter 'n'
+instead of as a newline.
+
+* lib/am/python.am [?FIRST?] (am__pep3147_tweak): Use a space instead of '\n'.
+* NEWS: Update.
+---
+ NEWS             | 8 ++++++++
+ lib/am/python.am | 2 +-
+ 2 files changed, 9 insertions(+), 1 deletion(-)
+
+--- lib/am/python.am.orig	2018-02-26 20:38:27 UTC
++++ lib/am/python.am
+@@ -97,7 +97,7 @@ endif %?INSTALL%
+ if %?INSTALL%
+ 
+ ?FIRST?am__pep3147_tweak = \
+-?FIRST?  sed -e 's|\.py$$||' -e 's|[^/]*$$|&.*.pyc\n&.*.pyo|'
++?FIRST?  sed -e 's|\.py$$||' -e 's|[^/]*$$|&.*.pyc &.*.pyo|'
+ 
+ .PHONY uninstall-am: uninstall-%DIR%PYTHON
+ uninstall-%DIR%PYTHON:
+-- 
+2.22.0
+