(CoUninitialize): Remove.
(CoCreateInstance): Remove.
(CoTaskMemFree): Add.
(SHGetDesktopFolder): Add.
* path.cc (shortcut_header): Remove.
(shortcut_initalized): Remove.
(GUID_shortcut): New static GUID.
(struct win_shortcut_hdr): New struct describing Windows shortcut
header structure.
(symlink_worker): Rewrite creating Windows shortcuts. Create
ITEMIDLIST if target exists. Only write once.
(cmp_shortcut_header): Use win_shortcut_hdr structure for comparison.
(check_shortcut): Rewrite to read only once from file. Allow skipping
an ITIMIDLIST in the file.