--- libtorrent-0.13.6.orig/scripts/ax_check_zlib.m4	2015-08-08 17:01:32.000000000 +0200
+++ libtorrent-0.13.6/scripts/ax_check_zlib.m4	2016-05-25 21:33:01.003893982 +0200
@@ -79,7 +79,7 @@ AC_ARG_WITH([zlib],
   AC_MSG_RESULT(yes)
   if test -d "$withval"
   then
-    zlib_places="$withval $zlib_places"
+    zlib_places="$withval"
   else
     AC_MSG_WARN([Sorry, $withval does not exist, checking usual places])
   fi