[oe] Variable reference (was: Documentation update about machine conf files)

[Steffen Sledz]

>> Would be nice if it is not a glossary only but contains additional info
>> (e.g. exact usage, restrictions, dependencies, examples). This may be
>> realized by references to an own (wiki) page for each variable which needs
>> more than a one liner.
>>
>> What's the community opinion? Should we start such an index in the wiki?
> 
> Long time ago, I created conf/documentation.conf. For every variable back then 
> we have used VAR[doc] = "Documentation" to describe the semantic of this 
> variable. A utility like bitdoc spit out a HTML page...
> 
> I would like to see this updated.

It's a good starting point. But it has one drawback: It allows a short one liner docu only. Often it would be great to have some more info, e.g. a list of supported image file system types for IMAGE_FSTYPES.

Steffen