[PATCH] gold: Skip address size and segment selector for DWARF5

[Cary Coutant]

> > The .debug_line secton in DWARF5 has a byte for address size and a byte
> > for segment selector after DWARF version.  Skip them for DWARF5.
> >
> >         PR gold/27246
> >         * dwarf_reader.cc (Sized_dwarf_line_info::read_header_prolog):
> >         Skip address size and segment selector for DWARF5.

This is OK for now, but probably isn't sufficient to prevent all
crashes. I'm working on adding DWARF 5 support.

-cary