add role attribute to anchor tags gtkdoc-mkdb produces

[Stefan Kost <ensonic hora-obscura de>]

hello,

I'd like to change all the OutputXXX function in gtkdoc-mkdb to write
not just

<title><anchor id="xxx"/>yyy</title>

but e.g.

<title><anchor id="xxx" role="macro"/>yyy</title>

instead. from the docbook point of view it is legal to use the 'role'
attribute for such purpose. [1][2]

On the base of this the devhelp.xsl script can be extended to not just
write out 'function' tags. I spoke to the devhelp developers and they
would like to show the type of symbol e.g. by an icon or allow to filter
on symbol types.

Other information that I'd like to go in there so that we can pass them
to devhelp are:
* deprecating status
* since
* stabillity

The docbook anchor tag has to following attributes for application usage:
* Arch
* Condition
* Conformance
* Revision
* Security
* UserLevel
* Vendor

'Condition' sounds like a good candidate to me, but would require that
we pack the data into this attribute in a form, where devhelp can easily
pare it. If we make this extensible we can transport future data the
same way. I have something like this in my head:

<title>
  <anchor id="xxx" role="macro" condition="since:2.2|deprecated:2.8"/>
  yyy
</title>
<title>
  <anchor id="xxx" role="function" condition="since:2.6|deprecated"/>
  yyy
</title>

Any comments. Should I have a go at it?

@mickael: du you want to keep the function tags for compatibillity. should the 
new format look like what you've posted to bugzilla [3]. Would another attribute 
 'condition' like shown above be okay. Then the xsl could just copy it 1:1.

Stefan


[1] http://www.docbook.org/tdg/en/html/anchor.html
[2] http://www.docbook.org/tdg/en/html/ref-elements.html#common.attributes
[3] http://bugzilla.gnome.org/show_bug.cgi?id=310542