Script updating of upstream files

doc/releases.txt

@@ -20,8 +20,11 @@ Before the release:
   ls | while read aa; do git log --follow --diff-filter=A --find-renames=40% --format="%ai  $aa" "$aa"; done > foo.log
 
   Then inspect foo.log for any files added since the last release.
-* Make sure that config.guess and config.sub are up-to-date (get them from
-  savannah.gnu.org/projects/config) (git clone is easiest)
+* Make sure that upstream files are up-to-date by running:
+
+  ./tools/update-upstream.sh
+
+  Requires curl or wget.
 * configure.ac: remove 'git' from textual version number, and increment it
 * run autoreconf --force but do *NOT* use the --install option as it will
   overwrite our custom ltmain.sh

tools/update-upstream.sh

@@ -0,0 +1,21 @@
+#!/bin/sh -u
+# tools/update-upstream.sh -- files to their latest version
+# Copyright (C) 2017  Olaf Meeuwissen
+#
+# License: GPL-3.0+
+
+fetch () {
+    if type curl 2>/dev/null >/dev/null ; then
+        curl --silent --remote-name $1
+        return
+    fi
+    if type wget 2>/dev/null >/dev/null ; then
+        wget --quiet --output-document $(echo $1 | sed 's,.*/,,') $1
+    fi
+}
+
+CONFIG_BASE_URL=http://git.savannah.gnu.org/cgit/config.git/plain
+
+for file in config.guess config.sub; do
+    fetch $CONFIG_BASE_URL/$file
+done