llvm/clang/test/VFS/Inputs/vfsoverlay-directory-relative.yaml

{
  'version': 0,
  'fallthrough': true,
  'overlay-relative': true,
  'roots': [
    { 'name': 'OUT_DIR',
      'type': 'directory-remap',
      'external-contents': 'INPUT_DIR'
    }
  ]
}