KWSys 2017-01-16 (a423d829)

Code extracted from:

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

at commit a423d82989a4b89fa7d17f3dd5215684e902208e (master).

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

Ben Boeckel (1):
      45db0937 SystemTools: use PathExists where appropriate

Brad King (1):
      e08eee61 SystemTools: Fix conversion warning in test case

Eric Berge (1):
      687fcd79 Add -lsocket for libcmsys.a build on SunOS

Gregor Jasny (1):
      0541ce21 SystemTools: Fix off-by-one in GetLineFromStream with size limit