[PATCH 1/2] libdw: Use correct CU to resolve file names in dwarf_decl_file.

[Mark Wielaard]

On Fri, 2020-05-08 at 18:50 +0200, Mark Wielaard wrote:
> dwarf_decl_file uses dwarf_attr_integrate to get the DW_AT_decl_file
> attribute. This means the attribute might come from a different DIE
> in a different CU. If so, we need to use the CU associated with the
> attribute, not the original DIE, to resolve the file name.
> 
> Also add a bit more documentation to dwarf_attr_integrate explaining
> that the attribute returned might come from a different CU (and even
> different Dwarf).

Pushed to master.