[DynInst_API:] [dyninst/dyninst] db7014: Fix Variable location parsing

[Sasha NÃcolas <noreply@xxxxxxxxxx>]

  Branch: refs/heads/dwarf_variable_location
  Home:   https://github.com/dyninst/dyninst
  Commit: db7014b09857178709c1822b5c2f7f80758696a1
      https://github.com/dyninst/dyninst/commit/db7014b09857178709c1822b5c2f7f80758696a1
  Author: Sasha Nicolas <sasha@xxxxxxxxxxx>
  Date:   2020-07-27 (Mon, 27 Jul 2020)

  Changed paths:
    M dwarf/src/dwarfHandle.C
    M symtabAPI/src/dwarfWalker.C

  Log Message:
  -----------
  Fix Variable location parsing

Start using elfutils' libdwfl to open binaries with dwarf data.
This fixes dwarf variable location parsing for relocatable objects.