[release-branch.go1.7] runtime: fix nanotime for macOS Sierra

In the beta version of the macOS Sierra (10.12) release, the
gettimeofday system call changed on x86. Previously it always returned
the time in the AX/DX registers. Now, if AX is returned as 0, it means
that the system call has stored the values into the memory pointed to by
the first argument, just as the libc gettimeofday function does. The
libc function handles both cases, and we need to do so as well.

Fixes golang#16272.

Change-Id: Ibe5ad50a2c5b125e92b5a4e787db4b5179f6b723
Reviewed-on: https://go-review.googlesource.com/24812
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-on: https://go-review.googlesource.com/24755
Reviewed-by: Chris Broadfoot <cbro@golang.org>

runtime: fix stale comment in lfstack

Change-Id: I6ef08f6078190dc9df0b2df4f26a76456602f5e8
Reviewed-on: https://go-review.googlesource.com/24176
Reviewed-by: Rick Hudson <rlh@golang.org>

api: promote next.txt to go1.7.txt and update api tool

Change-Id: Idb348be00f949da553aa6aab62836f59dfee298d
Reviewed-on: https://go-review.googlesource.com/23671
Reviewed-by: Chris Broadfoot <cbro@golang.org>
Run-TryBot: Andrew Gerrand <adg@golang.org>

[release-branch.go1.6] go1.6.2

Change-Id: Ifc545faaed438b72bfa63beb74cde2d3a67ef0e7
Reviewed-on: https://go-review.googlesource.com/22252
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

[release-branch.go1.6] go1.6.1

Change-Id: If172cf5ee0d2bde38581486f1c887d3d4826e95c
Reviewed-on: https://go-review.googlesource.com/21828
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Andrew Gerrand <adg@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

[release-branch.go1.5] go1.5.4

Change-Id: I7b62b2f358d2c2540e8d84e5c4739cfba73a19d1
Reviewed-on: https://go-review.googlesource.com/21827
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Andrew Gerrand <adg@golang.org>

go1.6

Change-Id: I5744bffe2af1706d9ac61d943aef18ce611cb623
Reviewed-on: https://go-review.googlesource.com/19580
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

[release-branch.go1.6] go1.6rc2

Change-Id: I7273f490cd99a74a8ed04d301b93c17a0ea6a117
Reviewed-on: https://go-review.googlesource.com/19204
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

[release-branch.go1.6] cmd/newlink: remove from release branch

Change-Id: Iec73b9a4279b5d6b458615c265e75b6becff320e
Reviewed-on: https://go-review.googlesource.com/19023
Run-TryBot: Chris Broadfoot <cbro@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

go/types: rename Importer2 to ImporterFrom

Per https://groups.google.com/forum/#!topic/golang-dev/javNmryAh0I

Change-Id: I08d7cbc94da4fc61c848f3dbee4637bf8fcfeb01
Reviewed-on: https://go-review.googlesource.com/18630
Reviewed-by: Alan Donovan <adonovan@google.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Chris Broadfoot <cbro@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>