attaching to a stopped process

[Tom Tromey]

There's a longstanding bug in gdb that it can't be run in the
background.  Normally this isn't such a big deal, but when running
insight it is natural to try to run it in the background.

Tonight I wanted to work on this bug.  So I ran insight in the
background, and then tried to attach to it like "gdb gdb 27783".

This didn't work -- my parent gdb just hung.

I had to go to original xterm and type "fg" to put the hung gdb into
the foreground before the "outer" gdb could fully attach to it.

This seems like a bug to me.

Tom