KWSys 2020-02-17 (3e117fe1)

Code extracted from:

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

at commit 3e117fe1e008aeca4a4f33a431b196848cc34e11 (master).

Upstream Shortlog
-----------------

Brad King (1):
      c2420a42 SystemTools: Revert "CopyFileIfDifferent: Ensure that source is a file"

Julien Schueller (1):
      c3acc96d CMake: Fix psapi lib name on case-sensitive fs

Sebastian Lipponer (2):
      573713fa SystemTools: CopyFileIfDifferent: Ensure that source is a file
      ea77593a SystemTools: CopyFileIfDifferent: Fix endless recursion