--- autoconf-2.69/tests/foreign.at.orig	2012-03-07 18:35:26.000000000 +0100
+++ autoconf-2.69/tests/foreign.at	2017-01-31 16:34:36.105261591 +0100
@@ -57,7 +57,7 @@
 # Make sure at-path contains something valid, and let the test suite
 # display it when verbose.  And fail, skipping would too easily hide
 # problems.
-AT_CHECK([sed -n ["s,^.*\`\\(/[^']*\\)'.*,\\1,p"] stdout], [0], [stdout])
+AT_CHECK([sed -n ["s,^.*[\`']\\(/[^']*\\)'.*,\\1,p"] stdout], [0], [stdout])
 AT_CHECK([test -f "`sed -n 1p stdout`"])
 
 # Older libtoolize installed everything but install-sh...