I've checked it the following revision of Nick's previous
patch (http://permalink.gmane.org/gmane.comp.gdb.devel/22707) that
makes variable object remember the thread they belong to.
I've tested this manually, proper thread and docs will be following
shortly.

Nick,
the changes I've made are as follows:

	- I use the valid_block instead of special -2 value
	to check if a varobj is global.
	- I did not use -1 value to indicate the thread is gone. Presently,
	we don't specifically mark variables object whose frame is gone,
	and I don't see why we should be do differently for threads.

If something seems wrong, please say.

Thansk,
Volodya