go/misc/dist: Keep file modes when copying.

R=adg
CC=golang-dev
https://codereview.appspot.com/7221055
A+C: Rodrigo Rafael Monti Kochenburger (individual CLA)

Generated by addca.

R=gobot
CC=golang-dev
https://codereview.appspot.com/7247043
runtime: implement range access functions in race detector.

Range access functions are already available in TSan library
but were not yet used.

Time for go test -race -short:

Before:
compress/flate 24.244s
exp/norm       >200s
go/printer     78.268s

After:
compress/flate 17.760s
exp/norm        5.537s
go/printer      5.738s

Fixes issue 4250.

R=dvyukov, golang-dev, fullung
CC=golang-dev
https://codereview.appspot.com/7229044
C: add Hossein Sheikh Attar (Google CLA)

R=golang-dev
CC=golang-dev
https://codereview.appspot.com/7241048
runtime: add support for panic/recover in Plan 9 note handler

This change also resolves some issues with note handling: we now make
sure that there is enough room at the bottom of every goroutine to
execute the note handler, and the `exitstatus' is no longer a global
entity, which resolves some race conditions.

R=rminnich, npe, rsc, ality
CC=golang-dev
https://codereview.appspot.com/6569068

Committer: Anthony Martin <ality@pbrane.org>