-var-show-attributes response syntax

[Vladimir Prus <vladimir@codesourcery.com>]

Hello!

Here's the docs for -var-show-attributes MI command:

       Synopsis 
            -var-show-attributes name

          List attributes of the specified variable object name: 
             status=attr [ ( ,attr )* ]
             where attr is { { editable | noneditable } | TBD }.

What is the reason for using "non" instead of "attribute_name=attribute_value" 
syntax? The above assumes all attributes are boolean, which is not very 
extensible.

How about changing the above to "editable=0/1"? This sounds like breaking 
backward compatibility, but probably is not, because "editable" is broken 
itself:

     -var-create C * 1+1
     ^done,name="C",numchild="0",type="long"
     (gdb)
     -var-show-attributes C
     ^done,attr="editable"
     (gdb)

Thoughts?

- Volodya