Bug 12142 – std.stdio should allow opening a Windows HANDLE

Windows C libraries expose APIs that allow binding a HANDLE to a file descriptor (which can then be fdopen-ed to a FILE*, and wrapped into a std.stdio.File). This functionality is already used by std.process, but user code can also benefit from the ability to use HANDLEs (which can be pipes and other devices) using std.stdio. Respectively, there should be a way to obtain a HANDLE back from a File. https://github.com/D-Programming-Language/phobos/pull/1888