To provide Windows-compatible functionality, spack code should use
llnl.util.symlink instead of os.symlink. On non-Windows platforms
and on Windows where supported, os.symlink will still be used.
Use junctions when symlinks aren't supported on Windows (#22583)
Support islink for junctions (#24182)
Windows: Update llnl/util/filesystem
* Use '/' as path separator on Windows.
* Recognizing that Windows paths start with '<Letter>:/' instead of '/'
Co-authored-by: lou.lawrence@kitware.com <lou.lawrence@kitware.com>
Co-authored-by: John Parent <john.parent@kitware.com>