Eric Bloodworth <ergosys@gmail.com> [Mon, 24 Oct 2005 14:54:34 -0700] rev 1428
Change asciidoc backend to more recent name.
The latest asciidoc doesn't have an 'html' backend. 'html' was last valid
with version 6 ( 2005-1-28). Current options are xhtml11, or
html4, with xhtml11 by default.