libdwfl: dwfl_linux_proc_find_elf use elf_from_remote_memory for (deleted).

If a module has a "(deleted)" main ELF file, then try to read it from
remote memory if the Dwfl has process state attached by reusing the ptrace
mechanism from linux-pid-attach.

Signed-off-by: Mark Wielaard <mjw@redhat.com>
5 files changed