(#17067) Load packaging tasks when available

This commit adds code to the Rakefile that loads packaging.rake if it exists.
That file defines tasks to fetch and remove the packaging tools, and to load
them when they are present.

Rakefile

@@ -1,4 +1,5 @@
 # Rakefile to build a project using HUDSON
+RAKE_ROOT = File.expand_path(File.dirname(__FILE__))
 
 begin
   require 'rdoc/task'
@@ -26,6 +27,11 @@ ENV["DEB_DISTRIBUTION"] ? PKG_DEB_DISTRIBUTION = ENV["DEB_DISTRIBUTION"] : PKG_D
 
 CLEAN.include(["build", "doc"])
 
+begin
+  load File.join(RAKE_ROOT, 'ext', 'packaging.rake')
+rescue LoadError
+end
+
 def announce(msg='')
   STDERR.puts "================"
   STDERR.puts msg

ext/packaging.rake

@@ -0,0 +1,36 @@
+build_defs_file = File.join(RAKE_ROOT, 'ext', 'build_defaults.yaml')
+if File.exist?(build_defs_file)
+  begin
+    require 'yaml'
+    @build_defaults ||= YAML.load_file(build_defs_file)
+  rescue Exception => e
+    STDERR.puts "Unable to load yaml from #{build_defs_file}:"
+    raise e
+  end
+  @packaging_url  = @build_defaults['packaging_url']
+  @packaging_repo = @build_defaults['packaging_repo']
+  raise "Could not find packaging url in #{build_defs_file}" if @packaging_url.nil?
+  raise "Could not find packaging repo in #{build_defs_file}" if @packaging_repo.nil?
+
+  namespace :package do
+    desc "Bootstrap packaging automation, e.g. clone into packaging repo"
+    task :bootstrap do
+      if File.exist?(File.join(RAKE_ROOT, "ext", @packaging_repo))
+        puts "It looks like you already have ext/#{@packaging_repo}. If you don't like it, blow it away with package:implode."
+      else
+        cd File.join(RAKE_ROOT, 'ext') do
+          %x{git clone #{@packaging_url}}
+        end
+      end
+    end
+    desc "Remove all cloned packaging automation"
+    task :implode do
+      rm_rf File.join(RAKE_ROOT, "ext", @packaging_repo)
+    end
+  end
+end
+
+begin
+  load File.join(RAKE_ROOT, 'ext', 'packaging', 'packaging.rake')
+rescue LoadError
+end