This adds an initial implementation for file operations on Windows. With
this, `FileManager` should at least build on Windows, which unblocks
future work as well as brings us closer to enabling
`FoundationEssentials` on Windows.
Implement the directory enumeration operations in FileManager on
Windows. The implementation uses the Win32 API surface to ensure that we
can use the full features of the platform.
Adjust the codepaths to improve Windows support in the file. This is
simply blindly trying to match semantics to reduce the errors reported
during building `FoundationEssentials`.
This adjusts the symbolic link paths to be supported on Windows. The
symbolic link destination computation is particularly gnarly as it
requires re-defining the device driver interface in a shim header to
access that and then performing aliasing contortions to gain access to
the trailing VLA to get the value.
This allows for us to use the constants without explicitly casting the
type to `DWORD` on each site of use. By providing the shadowing
overload we can simply use the constants without impacting the
readability of the surrounding code.
