test/run: always set goos and goarch

Following CL 68150047, the goos and goarch
variables are not currently set when the GOOS
and GOARCH environment variables are not set.

This made the content of the build tag to be
ignored in this case.

This CL sets goos and goarch to runtime.GOOS
and runtime.GOARCH when the GOOS and GOARCH
environments variables are not set.

LGTM=aram, bradfitz
R=golang-codereviews, aram, gobot, rsc, dave, bradfitz
CC=golang-codereviews, rsc
https://codereview.appspot.com/112490043
runtime: set sweepgen atomically before updating span state

Sweepone may be running while a new span is allocating.  It
must not see the state updated while the sweepgen is unset.

Fixes issue 8399

LGTM=dvyukov
R=golang-codereviews, dvyukov
CC=golang-codereviews
https://codereview.appspot.com/118050043
time: minor typo in doc

LGTM=minux
R=golang-codereviews, minux
CC=golang-codereviews
https://codereview.appspot.com/120150043

Committer: Shenghou Ma <minux@golang.org>
doc: drop scheme from links that are known to support HTTPS

golang.org now serves HTTPS with a valid cert, so it's reasonable
that users should click through to the HTTPS versions of *.golang.org
and other known sites.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://codereview.appspot.com/112650043
syscall: fix handling of bool return values in mksyscall_windows.go

LGTM=chines
R=chines
CC=golang-codereviews
https://codereview.appspot.com/118160044
cmd/gc: don't mark select descriptor as EscNone

selv is created with temp() which calls tempname, which marks
the new n with EscNever, so there is no need to explicitly set
EscNone on the select descriptor.

Fixes issue 8396.

LGTM=dvyukov
R=golang-codereviews, dave, dvyukov
CC=golang-codereviews
https://codereview.appspot.com/112520043

Committer: Dmitriy Vyukov <dvyukov@google.com>
include/u.h: define _DEFAULT_SOURCE for new glibc

glibc devs have apparently decided _BSD_SOURCE will be
deprecated on Linux, and issue a preprocessor warning if
declaring _BSD_SOURCE without _DEFAULT_SOURCE.

https://sourceware.org/glibc/wiki/Release/2.20

Fixes issue 8397.

LGTM=iant
R=dave, gobot, iant
CC=golang-codereviews
https://codereview.appspot.com/112530043

Committer: Ian Lance Taylor <iant@golang.org>
runtime: convert complex128div to go.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://codereview.appspot.com/116320043

--HG--
rename : src/pkg/runtime/complex.goc => src/pkg/runtime/complex.go