run_pre_install_hooks

# File lib/rubygems/installer.rb, line 345
  def run_pre_install_hooks # :nodoc:
    Gem.pre_install_hooks.each do |hook|
      if hook.call(self) == false
        location = " at #{$1}" if hook.inspect =~ /@(.*:\d+)/

        message = "pre-install hook#{location} failed for #{spec.full_name}"
        raise Gem::InstallError, message
      end
    end
  end