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>