os/exec: fix fd leak with Std*Pipe + LookPath

If LookPath in Command fails, sets a sticky error, and then
StdinPipe, StdoutPipe, or StderrPipe were called, those pipe
fds were never cleaned up.

Fixes issue 5071

R=golang-dev, rogpeppe
CC=golang-dev
https://codereview.appspot.com/7799046
database/sql: allow simultaneous queries, etc in a Tx

Now that revision 0c029965805f is in, it's easy
to guarantee that we never access a driver.Conn
concurrently, per the database/sql/driver contract,
so we can remove this overlarge mutex.

Fixes issue 3857

R=golang-dev, adg
CC=golang-dev
https://codereview.appspot.com/7707047
runtime: fix build for NetBSD/ARM

R=golang-dev, jsing
CC=golang-dev
https://codereview.appspot.com/7597046
runtime: fix tv_sec 32-bit overflows in sleep routines.

Fixes issue 5063.

R=golang-dev, minux.ma, rsc
CC=golang-dev
https://codereview.appspot.com/7876043
net/http: shorten and clean up TestTransportConcurrency

R=golang-dev, rsc
CC=golang-dev
https://codereview.appspot.com/7817044
net/http: add StripPrefix example; simplify code

The example is the same as the FileServer one, but
it's relevant for both.

Also use strings.TrimPrefix while I'm here.

R=golang-dev, rsc
CC=golang-dev
https://codereview.appspot.com/7598046
cmd/gc: steal escape analysis info when inlining

Usually, there is no esc info when inlining, but there will be when generating inlined wrapper functions.

If we don't use this information, we get invalid addresses on the stack.

Fixes issue 5056.

R=golang-dev, rsc
CC=golang-dev, remyoudompheng
https://codereview.appspot.com/7850045
doc/go1.1.html: document some of the library changes.
Still much to do, but this is a start.

R=golang-dev, adg, bradfitz, remyoudompheng
CC=golang-dev
https://codereview.appspot.com/7729046
database/sql: add DB.SetMaxIdleConns

Update issue 4805

R=golang-dev, r
CC=golang-dev
https://codereview.appspot.com/7634045
database/sql: doc cleanup on the DB type

R=golang-dev, adg
CC=golang-dev
https://codereview.appspot.com/7865044
doc/go1.1.html: document the surrogate and BOM changes

R=golang-dev, adg
CC=golang-dev
https://codereview.appspot.com/7853048
runtime: fix erroneous overflow protection on netbsd/openbsd semasleep.

On NetBSD tv_sec is already an int64 so no need for a test.

On OpenBSD, semasleep expects a Unix time as argument,
and 1<<30 is in 2004.

R=golang-dev, iant
CC=golang-dev
https://codereview.appspot.com/7810044