Re: [PATCH 1/2] doc: add an option to have Asciidoctor build man pages directly

> From: Felipe Contreras <felipe.contreras@gmail.com>
>> Asciidoctor contains a converter to generate man pages.  In some
> environments, where building only the manual pages and not the other
> documentation is desired, installing a toolchain for building
> DocBook-based manual pages may be burdensome, and using Asciidoctor
> directly may be easier, so let's add an option to build manual pages
> using Asciidoctor without the DocBook toolchain.
> > We generally require Asciidoctor 1.5, but versions before 1.5.3 didn't
> contain proper handling of the apostrophe, which is controlled normally
> by the GNU_ROFF option.  This option for the DocBook toolchain, as well
> as newer versions of Asciidoctor, makes groff output an ASCII apostrophe
> instead of a Unicode apostrophe in text, so as to make copy and pasting
> commands easier.  These newer versions of Asciidoctor detect groff and
> do the right thing in all cases, so the GNU_ROFF option is obsolete in
> this case.
> 
> We also need to update the code that tells Asciidoctor how to format our
> linkgit macros so that it can output proper code for man pages.  Be
> careful to reset the font to the previous after the change.  In order to
> do so, we must reset to the previous after each font change so the
> previous state at the end is the state before our inserted text, since
> troff only remembers one previous font.
> 
> Because Asciidoctor versions before 2.0 had a few problems with man page
> output, let's default this to off for now, since some common distros are
> still on 1.5.  If users are using a more modern toolchain or don't care
> about the rendering issues, they can enable the option.
> 
> Suggested-by: Bagas Sanjaya <bagasdotme@gmail.com>
> Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
> Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
> ---

> diff --git a/Documentation/asciidoctor-extensions.rb b/Documentation/asciidoctor-extensions.rb
> index d906a00803..40fa87b121 100644
> --- a/Documentation/asciidoctor-extensions.rb
> +++ b/Documentation/asciidoctor-extensions.rb
> @@ -15,6 +15,8 @@ module Git
>             "#{target}(#{attrs[1]})</ulink>"
>           elsif parent.document.basebackend? 'html'
>             %(<a href="#{prefix}#{target}.html">#{target}(#{attrs[1]})</a>)
> +        elsif parent.document.basebackend? 'manpage'
> +          %(\\fB#{target}\\fP\\fR(#{attrs[1]})\\fP)
>           elsif parent.document.basebackend? 'docbook'
>             "<citerefentry>\n" \
>               "<refentrytitle>#{target}</refentrytitle>" \
> diff --git a/Makefile b/Makefile
> index 93664d6714..cb75dec314 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -285,6 +285,9 @@ all::
>   # Define USE_ASCIIDOCTOR to use Asciidoctor instead of AsciiDoc to build the
>   # documentation.
>   #
> +# Define USE_ASCIIDOCTOR_MANPAGE to use Asciidoctor's manual page backend
> +# instead of building manual pages from DocBook.
> +#