[RFC] link GDB against libunwind-ia64

[Joel Brobecker <brobecker@adacore.com>]

Hello, 

I'm currently working on a GDB port for ia64-hpux, and I'm having some
problems with the unwinding of a stacked register. I'm trying to find
the source of the problem, and part of the investigation lead me to look
into the libunwind-ia64 code.

I noticed that GDB uses the libunwind-ia64 shared library without being
directly linked to it. Instead, it uses dlopen().

This method has its advantages, but also introduces an extra layer
of complication that is preventing me from making progress (*): A bug
in my debugger is causing problems when I am attempting operations such
as next or step over code inside that library.

So I'd like to add an option so that GDB is explicitly linked against
libunwind-ia64, instead of using dlopen(). As a bonus, this may simplify
our work in terms of binary distribution...

I was wondering if this would be an interesting enhancement to contribute.

Let me know...
-- 
Joel

(*): There is also the fact that it's tough to tell when you run GDB
     whether the libunwind unwinder has been initialized or not, since
     it depends on the success of the dlopen() and a few other operations.
     And when succesful, it's also tough to determine which one was used.