[DynInst_API:] [dyninst/dyninst] a0f27a: Add debuginfod support (#736)

[aaronmerey <noreply@xxxxxxxxxx>]

  Branch: refs/heads/master
  Home:   https://github.com/dyninst/dyninst
  Commit: a0f27a5d1d9c5582edd7c5ea39f950961d510f91
      https://github.com/dyninst/dyninst/commit/a0f27a5d1d9c5582edd7c5ea39f950961d510f91
  Author: aaronmerey <amerey@xxxxxxxxxx>
  Date:   2021-02-01 (Mon, 01 Feb 2021)

  Changed paths:
    M cmake/ElfUtils.cmake
    A cmake/Modules/FindLibDebuginfod.cmake
    M cmake/options.cmake
    M elf/CMakeLists.txt
    M elf/src/Elf_X.C

  Log Message:
  -----------
  Add debuginfod support (#736)

* Add debuginfod support

Debuginfod is a lightweight web service that indexes ELF/DWARF debugging
resources by build-id and serves them over HTTP.

This patch enables dyninst to query debuginfod servers for a file's
separate debuginfo when it otherwise cannot be found.

This patch also adds a cmake option -DENABLE_DEBUGINFOD to control
whether dyninst is built with debuginfod support.

This requires having the debuginfod client library (libdebuginfod)
and header installed.

Debuginfod is distributed with elfutils, for more information see
https://sourceware.org/elfutils/Debuginfod.html

* cmake/ElfUtils.cmake: Remove unnecessary for LibDebuginfod_FOUND and ENABLE_DEBUGINFOD