os/exec: LookPath on Unix shouldn't look in cwd when PATH is empty

R=golang-dev, dave, bradfitz
CC=golang-dev
https://codereview.appspot.com/7305053

Committer: Brad Fitzpatrick <bradfitz@golang.org>
net: skip TestMulticastListener on Solaris

R=golang-dev, minux.ma
CC=golang-dev
https://codereview.appspot.com/7308060
crypto/md5: fix for big-endian processors

R=golang-dev, minux.ma, agl
CC=golang-dev
https://codereview.appspot.com/7305059
cmd/8g: add a few missing splitclean

Fixes issue 887.

R=ken2
CC=golang-dev
https://codereview.appspot.com/7303061
bytes: minor optimization to lastIndexFunc

Before and after:
BenchmarkTrimSpace  20000000   81.3 ns/op
BenchmarkTrimSpace  50000000   58.0 ns/op

(most whitespace trimming is ASCII whitespace)

Same optimization appeared a handful of other places
in this file, but not here.

R=golang-dev, dave
CC=golang-dev
https://codereview.appspot.com/7305063
cmd/godoc: fix format strings.

R=golang-dev, bradfitz
CC=golang-dev
https://codereview.appspot.com/7309061
net: do not use RLock around Accept

It might be non-blocking, but it also might be blocking.
Cannot take the chance, as Accept might block indefinitely
and make it impossible to acquire ForkLock exclusively
(during fork+exec).

Fixes issue 4737.

R=golang-dev, dave, iant, mikioh.mikioh
CC=golang-dev
https://codereview.appspot.com/7309050
codereview: use hgapplydiff instead of hgpatch

Depends on https://codereview.appspot.com/7308067

R=golang-dev, bradfitz
CC=golang-dev
https://codereview.appspot.com/7312064
C: add Jeremy Schlatter (Google CLA)

R=golang-dev, dsymonds
CC=golang-dev
https://codereview.appspot.com/7307070
io: Simplify CopyN implementation by delegating to Copy.

R=golang-dev, dave, minux.ma, bradfitz, rsc
CC=golang-dev
https://codereview.appspot.com/7312055

Committer: Brad Fitzpatrick <bradfitz@golang.org>
runtime: fix build for Linux/ARM

R=dave, rsc
CC=golang-dev
https://codereview.appspot.com/7299055
cmd/5g: add missing splitclean.

See issue 887 for the 8g analogue.

R=golang-dev, minux.ma
CC=golang-dev
https://codereview.appspot.com/7306069
net: delete duplicate listenerSockaddr

R=golang-dev, dave
CC=golang-dev
https://codereview.appspot.com/7299067