This adds the recommended API for determining well-known folder paths,
such as where to place application configuration data. The MSDN
documentation mentions an optimization for the "current user" by passing
NULL as the token, so we provide both variants.
Updates golang/go#32248
Change-Id: I4a2d5d833543e6a0ba8f318944dd6493a0ec31d3
Reviewed-on: https://go-review.googlesource.com/c/sys/+/181637
Reviewed-by: Jason Donenfeld <Jason@zx2c4.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Run-TryBot: Jason Donenfeld <Jason@zx2c4.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
