[bug#42882]

[Maxim Cournoyer]

Hello Mathieu,

Thanks for the review!  I've taken into account your suggestions and improved
the mechanism a bit, so that we can now simply use the
GDB_DEBUG_FILE_DIRECTORY environment variable (which is set up by a new search
path specification defined on the gdb package). I think this is better as
otherwise you'd need to ensure the gcc-toolchain is installed in the profile
you want GDB to find the debug files (because GCC is responsible for setting
the LIBRARY_PATH environment variable).

I hope it makes sense :-).

This will need to go to core-updates as gdb is has about 1500 dependents.

Thanks!

Maxim