Add tool to update GMSL

Signed-off-by: Timothy Gu <timothygu99@gmail.com>

tools/update-gmsl

@@ -0,0 +1,45 @@
+#!/bin/sh
+# This file is part of MXE.
+# See index.html for further information.
+#
+# Script to automatically update GNU Make Standard Library
+# (http://gmsl.sourceforge.net/)
+
+clean(){
+    rm -rf tmp-gmsl.tar.gz gmsl-*
+}
+
+# Ported from main Makefile
+SED='sed'
+SORT='sort'
+if [ gsed --help >/dev/null 2>&1 ]; then
+    SED='gsed'
+fi
+if [ gsort --help >/dev/null 2>&1 ]; then
+    SED='gsort'
+fi
+WGET="wget --no-check-certificate
+         --user-agent=$(wget --version |
+         $SED -n 's,GNU \(Wget\) \([0-9.]*\).*,\1/\2,p')"
+
+# Current GMSL version. E.g. '1.1.5'
+current_version=$(grep 'gmsl_version.*=' 'ext/__gmsl' | \
+                  cut -d'=' -f2 | $SED -e 's/^ //' -e 's/ *$//' | tr ' ' '.')
+# Latest GMSL version fetched from SourceForge
+latest_version=$(
+    $WGET -q -O- http://sourceforge.net/projects/gmsl/files/GNU%20Make%20Standard%20Library/ | \
+    $SED -n 's,.*/v\([0-9][^"]*\)/".*,\1,p' | \
+    $SORT -V | \
+    tail -1)
+
+clean
+if [ $current_version != $latest_version ]; then
+    $WGET -q -O tmp-gmsl.tar.gz \
+        "http://downloads.sourceforge.net/project/gmsl/GNU%20Make%20Standard%20Library/v${latest_version}/gmsl-${latest_version}.tar.gz"
+    tar xzf tmp-gmsl.tar.gz
+    rm -f ext/*gmsl doc/gmsl*
+    cp -a gmsl-${latest_version}/gmsl ext/
+    cp -a gmsl-${latest_version}/__gmsl ext/
+    cp -a gmsl-${latest_version}/index.html doc/gmsl.html
+    clean
+fi