[Proposal] GDB honouring RPATH in binaries.

[Kris Warkentin]

> So, I have two potential solutions:
>
> One: We could add something like 'vendor-solib-search-path' which could be
> searched so that solib-search-path can be left for the user.  Then vendors
> can just initialize v-s-s-p and users don't have to worry.
>
> Two: provide a mechanism to append strings to gdb variables such as
> solib-search-path which might be useful in other situations.  A really
nice
> implementation would be some form of variable expansion, ie:
>
> set solib-search-path $solib-search-path:/home/foo
>

Ooh ooh....number 3 just came to mind.  In solib_open(), we go through a
bunch of, "Lib not found yet? Okay, try this.  Still not found?  Okay, try
this".

We could just make a target_ops solib_open_hook that returns a fd to the lib
in some vendor/target defined way.  Then, in solib_open(), we just check to
see if the hook is there and try to open the lib with that.  This would work
really well because then we can adjust on the fly to endian issues, etc.
ie. $QNX_TARGET/armbe or armle.

Kris