--- autoconf/ast_prog_sed.m4.orig	2009-01-14 13:53:44.000000000 +0100
+++ autoconf/ast_prog_sed.m4	2009-01-14 14:16:23.000000000 +0100
@@ -12,7 +12,8 @@
      done
      echo "$ac_script" | sed 99q >conftest.sed
      $as_unset ac_script || ac_script=
-     _AC_PATH_PROG_FEATURE_CHECK(SED, [sed gsed],
+     ifdef([_AC_PATH_PROGS_FEATURE_CHECK],[],[define([_AC_PATH_PROGS_FEATURE_CHECK],defn([_AC_PATH_PROG_FEATURE_CHECK]))])
+     _AC_PATH_PROGS_FEATURE_CHECK(SED, [sed gsed],
 	[_AC_FEATURE_CHECK_LENGTH([ac_path_SED], [ac_cv_path_SED],
 		["$ac_path_SED" -f conftest.sed])])])
  SED="$ac_cv_path_SED"