list preferred autotools

Original commit message from CVS:
list preferred autotools
diff --git a/autogen.sh b/autogen.sh
index 12031b7..281175f 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -28,10 +28,14 @@
 
 echo -n "+ check for build tools"
 if test ! -z $NOCHECK; then echo " skipped"; else  echo; fi
-version_check "autoconf" "$AUTOCONF" "ftp://ftp.gnu.org/pub/gnu/autoconf/" 2 52 || DIE=1
-version_check "automake" "$AUTOMAKE" "ftp://ftp.gnu.org/pub/gnu/automake/" 1 5 || DIE=1
-version_check "libtool" "" "ftp://ftp.gnu.org/pub/gnu/libtool/" 1 4 0 || DIE=1
-version_check "pkg-config" "" "http://www.freedesktop.org/software/pkgconfig" 0 8 0 || DIE=1
+version_check "autoconf" "$AUTOCONF autoconf autoconf-2.53 autoconf-2.52" \
+              "ftp://ftp.gnu.org/pub/gnu/autoconf/" 2 52 || DIE=1
+version_check "automake" "$AUTOMAKE automake automake-1.6 automake-1.5" \
+              "ftp://ftp.gnu.org/pub/gnu/automake/" 1 5 || DIE=1
+version_check "libtool" "" \
+              "ftp://ftp.gnu.org/pub/gnu/libtool/" 1 4 0 || DIE=1
+version_check "pkg-config" "" \
+              "http://www.freedesktop.org/software/pkgconfig" 0 8 0 || DIE=1
 
 die_check $DIE