Unless the first element is a Universal Naming Convention (UNC)[0]
path, Join shouldn't create a UNC path on Windows.
For example, Join inadvertently creates a UNC path on Windows when
told to join at least three non-empty path elements, where the first
element is `\` or `/`.
This CL prevents creation of a UNC path prefix when the first path
element isn't a UNC path.
Since this introduces some amount of Windows-specific logic, Join is
moved to a per GOOS implementation.
Fixes#9167.
[0]: http://msdn.microsoft.com/en-us/library/gg465305.aspx
Change-Id: Ib6eda597106cb025137673b33c4828df1367f75b
Reviewed-on: https://go-review.googlesource.com/2211
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Fix style by removing unnecessary named result parameter.
Fix doc comment while here.
Change-Id: If8394e696ab37e00a95484d5137955aa06c59520
Reviewed-on: https://go-review.googlesource.com/1781
Reviewed-by: Yasuhiro MATSUMOTO <mattn.jp@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
