[RFA/RFC] Fix broken user-thread debugging on x86-solaris

[Joel Brobecker]

> > In this version, I went to the simplest, which is to have configure
> > define a new macro (HAVE_X86_SOLARIS_USER_THREADS) when on x86-solaris
> > and the thread_db library is available.  I then replaced TM_I386SOL2_H
> > by the new macro.
> 
> How about just #if defined(__i386__) || defined(__x86_64__), if we're
> going to use macros?

I don't mind, but we also need to check for solaris too, since
procfs is used with other OSes as well. So something like this?

    #if (defined(__i386__) || defined(__x86_64__)) && defined (sun)

It's funny you would prefer this approach over the more functional
macro - I thought that people would crucify me if I suggested something
like this :). Would you prefer to isolate the code in a separate file
like I also suggested?

-- 
Joel