autoconf-mode is a major mode for editing Autoconf
configure.ac files, and macro files such as
There are two versions of this mode.
autoconf.el by DaveLove comes with Emacs 21 and 22, and
autoconf-mode.el by MartinBuchholz comes with XEmacs 21 and is in the Autoconf sources. Both are quite simple, and very similar, just offering basic syntax setups (including comment syntax) and FontLockKeywords. The
autoconf.el one has ImenuMode support too.