尝试在 RHEL 5.5 上安装 emacs 时，出现以下错误：
$ sudo yum install emacs
Loaded plugins: rhnplugin, security
This system is not registered with RHN.
RHN support will be disabled.
Setting up Install Process
No package emacs available.
Nothing to do
我已经安装了 rpmforge。当我尝试搜索 emacs 时，我得到以下信息：
================================================= Matched: emacs ==================================================
crm114-emacs.x86_64 : Emacs mode for CRM114
ed.x86_64 : The GNU line editor.
emacs-git.x86_64 : Git version control system support for Emacs
emacs-ocaml.x86_64 : Emacs mode for Objective Caml
gpm.i386 : A mouse server for the Linux console.
gpm.x86_64 : A mouse server for the Linux console.
ne.x86_64 : Nice editor
perl-Games-Dissociate.noarch : Dissociated Press algorithm and filter
ratpoison.x86_64 : Ratpoison window manager
readline.i386 : A library for editing typed command lines.
readline.x86_64 : A library for editing typed command lines.
sylpheed.x86_64 : Full-featured GTK+ based fast e-mail client
texmacs.x86_64 : Structured WYSIWYG scientific text editor
我在哪里可以找到 emacs？（或者我必须从源代码下载和编译？）谢谢