gold Symbol::should_add_dynsym_entry

[Cary Coutant]

> Seems to me that the following code in should_add_dynsym_entry() is
> a duplicate of code setting is_defined_in_discarded_section_.
> Unless is_section_included() and is_section_folded() can return
> different results here than at Add_symbols time?

Yes, I think they can return different results here. GC and ICF both
run after the Add_symbols tasks, so the answers can change. The symbol
attribute is true when it's in a discarded COMDAT section, but will
not be true if it's in a section discarded by GC or folded by ICF.

-cary