cmd/gc: make inlined labels distinct

Fixes issue 4748.

R=ken2
CC=golang-dev
https://codereview.appspot.com/7261044
xml: omit newline at beginning of MarshalIndent output

(Still valid XML.)

Fixes issue 3354.

R=golang-dev, dave
CC=golang-dev
https://codereview.appspot.com/7288047

Committer: Russ Cox <rsc@golang.org>
cmd/5l, cmd/ld: support generating ELF binaries for NetBSD/ARM

R=golang-dev, dave
CC=golang-dev
https://codereview.appspot.com/7261043
cmd/go: update 'go get' help message

It accepts all the build flags.
Say that instead of making a copy that will go stale.

Fixes issue 4742.

R=golang-dev, minux.ma
CC=golang-dev
https://codereview.appspot.com/7229081
cmd/gc: implement latest rules for checking make sizes

Fixes issue 4085.

R=ken2
CC=golang-dev
https://codereview.appspot.com/7277047
A+C: add Yusuke Kagiwada (Individual CLA)

R=golang-dev, rsc
CC=golang-dev
https://codereview.appspot.com/7292043
cmd/gc: slightly better code generation

* Avoid treating CALL fn(SB) as justification for introducing
and tracking a registerized variable for fn(SB).

* Remove USED(n) after declaration and zeroing of n.
It was left over from when the compiler emitted more
aggressive set and not used errors, and it was keeping
the optimizer from removing a redundant zeroing of n
when n was a pointer or integer variable.

Update issue 597.

R=ken2
CC=golang-dev
https://codereview.appspot.com/7277048