Generalize the FFI import script to also import lib/truffle/ffi

Author: eregon

tool/import-ffi-spec.sh

@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+
+set -x
+set -e
+
+repo="../../ffi"
+
+# lib/
+rm -rf lib/truffle/ffi
+cp -R ../../ffi/lib/ffi lib/truffle
+
+# Keep the empty pointer.rb file, these methods are already defined in core
+# and they need to be in core as there are usages in core.
+git checkout lib/truffle/ffi/pointer.rb
+
+# spec/
+rm -rf spec/ffi
+cp -R "$repo/spec/ffi" spec
+
+# Keep the Gemfile files
+git checkout spec/ffi/Gemfile spec/ffi/Gemfile.lock
+
+
+# Remove unused files
+rm -rf spec/ffi/embed-test