nghttp2: Add script to import from upstream

Utilities/Scripts/update-nghttp2.bash

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+
+set -e
+set -x
+shopt -s dotglob
+
+readonly name="nghttp2"
+readonly ownership="nghttp2 upstream <kwrobot@kitware.com>"
+readonly subtree="Utilities/cmnghttp2"
+readonly repo="https://github.com/nghttp2/nghttp2.git"
+readonly tag="v1.40.0"
+readonly shortlog=false
+readonly paths="
+  COPYING
+  lib/*.c
+  lib/*.h
+  lib/includes/nghttp2/nghttp2.h
+  lib/includes/nghttp2/nghttp2ver.h.in
+"
+
+extract_source () {
+    git_archive
+    pushd "${extractdir}/${name}-reduced"
+    echo "* -whitespace" > .gitattributes
+    mv lib/includes/nghttp2/nghttp2ver.h.in lib/includes/nghttp2/nghttp2ver.h
+    sed -i 's/@PACKAGE_VERSION@/1.40.0/;s/@PACKAGE_VERSION_NUM@/0x012800/' lib/includes/nghttp2/nghttp2ver.h
+    popd
+}
+
+. "${BASH_SOURCE%/*}/update-third-party.bash"