Remove nested functions from readelf.c

[Mark Wielaard]

On Fri, 2021-01-08 at 09:16 +0100, Timm Bäder via Elfutils-devel wrote:
> here another round for src/readelf.c. I think they are simple, but I'm
> not happy with the advance_pc() commit. I'm open for suggestions here
> but I can't come up with something better right now. I'll keep looking
> in to that in the meantime.

Yeah, the advance_pc function is really why you want nested functions
in the first place IMHO. Passing around the captured state as 6 extra
arguments seems to not really make the code much clearer. Especially
because on its own it isn't immediately clear what the code is about or
that it is to be used as part of the special opcode or
DW_LNS_advance_pc opcode (where DW_LNS_const_add_pc acts like special
opcode 255) handling.

It might be helpful to spell out in a comment to the function which
part of the DWARF4 6.2.5.1 Special Opcodes handling the advance_pc
function is responsible for.

But honestly in this case I think just keeping the nested function is
the cleanest way to handle this.

Cheers,

Mark