Change crew and lib/package.rb to add postinstall process.

crew

@@ -424,6 +424,13 @@ def build_and_preconfigure (target_dir)
   end
 end
 
+def post_install (target_dir)
+  Dir.chdir target_dir do
+    puts "Performing post-install..."
+    @pkg.postinstall
+  end
+end
+
 def compress_doc (dir)
   # check whether crew should compress
   return if CREW_NOT_COMPRESS || !File.exist?("#{CREW_PREFIX}/bin/compressdoc")
@@ -610,6 +617,9 @@ def install
     install_package dest_dir
   end
 
+  # perform post-install process
+  post_install target_dir
+
   #add to installed packages
   @device[:installed_packages].push(name: @pkg.name, version: @pkg.version)
   File.open(CREW_CONFIG_PATH + 'device.json', 'w') do |file|

lib/package.rb

@@ -69,10 +69,23 @@ class Package
     @is_fake
   end
 
+  # Function to perform build from source.
   def self.build
 
   end
 
+  # Function to perform install from source build.
+  def self.install
+
+  end
+
+  # Function to perform post-install for all even if it is a fake package.
+  def self.postinstall
+
+  end
+
+  # Function to perform check from source build.
+  # This is execute if and only if `crew build`.
   def self.check
 
   end