libffi: Add HOWTO_MERGE, autogen.sh and merge.sh

Add scripts for syncing with libffi upstream:

1. Clone libffi repo.
2. Checkout the specific commit.
3. Remove the unused files.
4. Add new files and remove old files if needed.

	* HOWTO_MERGE: New file.
	* autogen.sh: Likewise.
	* merge.sh: Likewise.

1 files changed, 51 insertions, 0 deletions

diff --git a/libffi/merge.sh b/libffi/merge.sh
new file mode 100755
index 00000000000..b36fbb92185
--- /dev/null
+++ b/libffi/merge.sh
@@ -0,0 +1,51 @@
+#!/bin/bash
+
+# FIXME: do we need a license (or whatever else) header here?
+
+# This script merges libffi sources from upstream.
+
+# Default to the tip of master branch.
+commit=${1-master}
+
+fatal() {
+  echo "$1"
+  exit 1;
+}
+
+get_upstream() {
+  rm -rf upstream
+  git clone https://github.com/libffi/libffi.git upstream
+  pushd upstream
+  git checkout $commit || fatal "Failed to checkout $commit"
+  popd
+}
+
+get_current_rev() {
+  cd upstream
+  git rev-parse HEAD
+}
+
+pwd | grep 'libffi$' || \
+  fatal "Run this script from the libffi directory"
+get_upstream
+CUR_REV=$(get_current_rev)
+echo Current upstream revision: $CUR_REV
+
+# Remove the unused files.
+pushd upstream
+rm -rf ChangeLog.old .appveyor* .ci .github .gitignore .travis* \
+	config.guess config.sub libtool-ldflags m4 make_sunver.pl \
+	msvc_build
+rm -rf .git autogen.sh
+cp -a . ..
+popd
+
+rm -rf upstream
+
+# Update the MERGE file.
+cat << EOF > MERGE
+$CUR_REV
+
+The first line of this file holds the git revision number of the
+last merge done from the master library sources.
+EOF