KWSys 2021-07-26 (d5fd6ca2)

Code extracted from:

    https://gitlab.kitware.com/utils/kwsys.git

at commit d5fd6ca2ba5b4ca04d7ac346ceb87f7d2b0ad8aa (master).

Upstream Shortlog
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Dženan Zukić (1):
      7079df74 SystemTools: Fix GetOperatingSystemNameAndVersion empty string return

Đoàn Trần Công Danh (1):
      4e69b791 SystemInformation: Add option to explicitly avoid using execinfo