It makes them work in Schannel's CA bundle loader, and curl tool's
set/get file timestamp operations (e.g. in `-R`/`--remote-time`). Also
to match file open operations, that already support long filenames.
E.g. when using `--remote-time`, fixing:
```
Warning: Failed to set filetime 1741363917 on outfile: CreateFile failed:
Warning: GetLastError 0x00000003
```
The special long filename logic is necessary to support Windows releases
prior to Windows 10 v1607. With the latter, it's possible to opt-in to
this behavior via a manifest setting. Note that Windows itself also needs
to opt-in to support this. Finally note that curl itself needs passing
`--globoff` to let long filenames through, pending #20044 and #20046.
Refs:
https://learn.microsoft.com/windows/win32/api/fileapi/nf-fileapi-createfileahttps://learn.microsoft.com/windows/win32/fileio/maximum-file-path-limitation
Ref: #8361
Inspired by: #19286
Inspired-by: Mathesh V
Closes#19286Closes#20040