def build_id
      section = section_by_name('.note.gnu.build-id')
      return nil if section.nil?

      note = section.notes.first
      return nil if note.nil?

      note.desc.unpack('H*').first
    end
def build_id
      section = section_by_name('.note.gnu.build-id')
      return nil if section.nil?

      note = section.notes.first
      return nil if note.nil?

      note.desc.unpack('H*').first
    end
Return the BuildID of ELF.
 @return [String, nil]
   BuildID in hex form will be returned.
   +nil+ is returned if the .note.gnu.build-id section
   is not found.
 @example
   elf.build_id
   #=> '73ab62cb7bc9959ce053c2b711322158708cdc07'