$NetBSD: patch-configure,v 1.3 2017/07/22 13:07:04 adam Exp $

On Darwin, use system libtool.

--- configure.orig	2017-07-22 06:56:04.000000000 +0000
+++ configure
@@ -2927,7 +2927,7 @@ echo "STRIP=@$strip" >> config.mak
 echo "WINDRES=$windres" >> config.mak
 fi
 echo "INSTALL=$install" >> config.mak
-echo "LIBTOOL=libtool" >> config.mak
+echo "LIBTOOL=/usr/bin/libtool" >> config.mak
 
 echo "INSTFLAGS=$instflags" >> config.mak
 echo "OPTFLAGS=$CFLAGS" >> config.mak