[RFA/stabs] fix failed assertion during replacement of undefined type

[Joel Brobecker]

> 2008-04-03  Joel Brobecker  <brobecker@adacore.com>
> 
>         * stabsread.c (cleanup_undefined_types_1): Add instance flags check
>         in the search for the matching symbol.
> 
[...]
> 2008-04-03  Joel Brobecker  <brobecker@adacore.com>
> 
> 	* gdb.ada/atomic_enum: New test program.
>       * gdb.ada/atomic_enum.exp: New testcase.
> 

I have applied this patch. I know Daniel was a little disgusted at the stabs
entry that this patch is trying to handle and wasn't very enthousiastic at
getting this one in. I'm putting it in because I think it can help others
outside of AdaCore customers, but I'm absolutely OK with backing it out.

-- 
Joel