Fixes #3773.

R=bradfitz, rsc
CC=golang-dev
https://golang.org/cl/6327053

- receiving from a closed channel returns immediately
- in the ,ok form, the 2nd result is of type bool, not
  just boolean (gc and ggcgo agree).

Per dsymonds' suggestion.

R=r, rsc, ken, iant, dsymonds
CC=golang-dev
https://golang.org/cl/6333057

This is a new, not yet committed API.

- Changed NewCommentMap to be independent of
  *File nodes and more symmetric with the
  Filter and Comments methods.

- Implemented Update method for use in
  AST modifications.

- Implemented String method for debugging

R=rsc
CC=golang-dev
https://golang.org/cl/6303086

Fixes #3713.

R=bradfitz, rsc
CC=golang-dev
https://golang.org/cl/6331055

A few performance improvements, but without the stack sorting
change to avoid allocating, which is instead waiting on better
escape analysis.

R=rsc
CC=golang-dev
https://golang.org/cl/6265047

This CL resolves https://golang.org/cl/6300043/#msg3
by renaming memset_arm.s to memclr_arm.s and merging the function
of the same name from asm_arm.s.

R=minux.ma, rsc
CC=golang-dev
https://golang.org/cl/6336054

The issue seems to not be triggered right now,
but I've seen the deadlock after some other legal
modifications to runtime.
So I think we are safer this way.

R=rsc, r
CC=golang-dev
https://golang.org/cl/6339051

This can only happen if the hash function we're using is getting
far more than it's fair share of collisions, but that has happened
to us repeatedly as we've expanded the allowed use cases for
hash tables (issue 1544, issue 2609, issue 2630, issue 2883, issue 3695).
Maybe this will help the next time we try something new.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6306083

pkg/math/all_test.go tests Atan (and therefore Asin and Acos) to a
relative accuracy of 4e-16, but the test vector misses values where
the old algorithm was in error by more than that. For example:

x            newError   oldError
0.414215746  1.41e-16  -4.24e-16
0.414216076  1.41e-16  -4.24e-16
0.414217632  1.41e-16  -4.24e-16
0.414218770  1.41e-16  -4.24e-16
0.414225466  0         -5.65e-16
0.414226244  1.41e-16  -4.24e-16
0.414228756  0         -5.65e-16
0.414235089  0         -5.65e-16
0.414237070  0         -5.65e-16

R=rsc, golang-dev
CC=golang-dev
https://golang.org/cl/6302093

Skip directory check in startProcess in the presence of
SysProcAttr.

Fixes #3649.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6297083

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6327054

Fixes #3732.

R=golang-dev
CC=golang-dev
https://golang.org/cl/6335053

Fixes #3714.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6341047

Fixes #3718.

Requires CL 6300043.

R=rsc, minux.ma, extraterrestrial.neighbour
CC=golang-dev
https://golang.org/cl/6305100

Partially fixes issue 3718.

R=golang-dev, rsc, minux.ma
CC=golang-dev
https://golang.org/cl/6300043

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6341046

Note url.Error wrapping, and s/issue/issuing/.

Fixes #3724

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/6294093

        We need to use kernel headers to generate defs_linux_$GOARCH.h

R=golang-dev, dave, alex.brainman, iant
CC=golang-dev
https://golang.org/cl/6296091

Several of my students were confused by trying to use both the error
return and a reply return, so I figured it was worth explicitly clarifying
that returning an error overrides the reply.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6327051

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6325053

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6337047

Use code to be used in lisp programs as suggested in the doc strings for
replace-{string|regexp}. Bonus: This code works for XEmacs.

R=golang-dev, sameer, jmeurin
CC=golang-dev
https://golang.org/cl/6296073

Flame motivated me to get around to adding extended key usage support
so that code signing certificates can't be used for TLS server
authentication and vice versa.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6304065

based on UCA test files.

R=r
CC=golang-dev
https://golang.org/cl/6216056

        Fixes #3753.

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/6304097

        if we were to use sizeof(sa.sa_mask) instead of 8 as the last argument
        to rt_sigaction, we would have already fixed this bug, so also updated
        Linux/386 and Linux/amd64 files to use that; also test the return value
        of rt_sigaction.

R=dave, rsc
CC=golang-dev
https://golang.org/cl/6297087

If the server replies with an HTTP response before we're done
writing our body (for instance "401 Unauthorized" response), we
were previously ignoring that, since we returned our write
error ("broken pipe", etc) before ever reading the response.
Now we read and write at the same time.

Fixes #3595

R=rsc, adg
CC=golang-dev
https://golang.org/cl/6238043

Also, fixes one violation found during testing where both
response and error could be non-nil when a CheckRedirect test
failed.  This is arguably a minor API (behavior, not
signature) change, but it wasn't documented either way and was
inconsistent & non-Go like.  Any code depending on the old
behavior was wrong anyway.

R=adg, rsc
CC=golang-dev
https://golang.org/cl/6307088

R=rsc, dsymonds
CC=golang-dev
https://golang.org/cl/6303099

R=r
CC=golang-dev
https://golang.org/cl/6301096

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/6303098

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6312045

A comment to that effect was introduced
with rev d332f4b9cef5 but the respective
code wasn't deleted.

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/6304086

        Fixes #3716.

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/6310044

R=r, dsymonds
CC=golang-dev
https://golang.org/cl/6298085

        Fixes #3739.

R=bradfitz, rsc
CC=golang-dev
https://golang.org/cl/6295083

        Fixes #3735.

R=golang-dev, agl
CC=golang-dev
https://golang.org/cl/6301083

R=golang-dev, rsc, dsymonds, minux.ma
CC=golang-dev
https://golang.org/cl/6305089

R=golang-dev, dave, rsc
CC=golang-dev
https://golang.org/cl/6298079

GOARCH=amd64 benchmarks

src/pkg/runtime
benchmark                  old ns/op    new ns/op    delta
BenchmarkConvT2ESmall             10           10   +1.00%
BenchmarkConvT2EUintptr            9            0  -92.07%
BenchmarkConvT2EBig               74           74   -0.27%
BenchmarkConvT2I                  27           26   -3.62%
BenchmarkConvI2E                   4            4   -7.05%
BenchmarkConvI2I                  20           19   -2.99%

test/bench/go1
benchmark                 old ns/op    new ns/op    delta
BenchmarkBinaryTree17    5930908000   5937260000   +0.11%
BenchmarkFannkuch11      3927057000   3933556000   +0.17%
BenchmarkGobDecode         21998090     21870620   -0.58%
BenchmarkGobEncode         12725310     12734480   +0.07%
BenchmarkGzip             567617600    567892800   +0.05%
BenchmarkGunzip           178284100    178706900   +0.24%
BenchmarkJSONEncode        87693550     86794300   -1.03%
BenchmarkJSONDecode       314212600    324115000   +3.15%
BenchmarkMandelbrot200      7016640      7073766   +0.81%
BenchmarkParse              7852100      7892085   +0.51%
BenchmarkRevcomp         1285663000   1286147000   +0.04%
BenchmarkTemplate         566823800    567606200   +0.14%

I'm not entirely sure why the JSON* numbers have changed, but
eyeballing the profile suggests that it could be spending less
and more time in runtime.{new,old}stack, so it could simply be
stack-split boundary noise.

R=rsc, dave, bsiegert, dsymonds
CC=golang-dev
https://golang.org/cl/6280049