time: fix panic with time.Parse(time.StampNano, ... )

Fixes issue 4502.

R=rsc
CC=golang-dev
https://codereview.appspot.com/6949058
debug/elf: handle missing shstrndx in core files

Fixes issue 4481.

hello-world-core.gz was generated with a simple hello world c program and core dumped as suggested in the issue.

Also: add support for gz compressed test fixtures.

R=minux.ma, rsc, iant
CC=golang-dev
https://codereview.appspot.com/6936058
cmd/6g: fix componentgen for funarg structs.

Fixes issue 4518.

R=golang-dev, rsc
CC=golang-dev
https://codereview.appspot.com/6932045
exp/gotype: disable failing tests and add a few more

R=rsc, alex.brainman
CC=golang-dev
https://codereview.appspot.com/6948066
go/doc: add "hdr-" prefix to headers generated from package overviews.

R=golang-dev, bradfitz, gri
CC=golang-dev
https://codereview.appspot.com/6935071
runtime: use clock_gettime to get ns resolution for time.now & runtime.nanotime

For Linux/{386,arm}, FreeBSD/{386,amd64,arm}, NetBSD/{386,amd64}, OpenBSD/{386,amd64}.
Note: our Darwin implementation already has ns resolution.

Linux/386 (Core i7-2600 @ 3.40GHz, kernel 3.5.2-gentoo)
benchmark       old ns/op    new ns/op    delta
BenchmarkNow          110          118   +7.27%

Linux/ARM (ARM Cortex-A8 @ 800MHz, kernel 2.6.32.28 android)
benchmark       old ns/op    new ns/op    delta
BenchmarkNow          625          542  -13.28%

Linux/ARM (ARM Cortex-A9 @ 1GHz, Pandaboard)
benchmark       old ns/op    new ns/op    delta
BenchmarkNow          992          909   -8.37%

FreeBSD 9-REL-p1/amd64 (Dell R610 Server with Xeon X5650 @ 2.67GHz)
benchmark       old ns/op    new ns/op    delta
BenchmarkNow          699          695   -0.57%

FreeBSD 9-REL-p1/amd64 (Atom D525 @ 1.80GHz)
benchmark       old ns/op    new ns/op    delta
BenchmarkNow         1553         1658   +6.76%

OpenBSD/amd64 (Dell E6410 with i5 CPU M 540 @ 2.53GHz)
benchmark       old ns/op    new ns/op    delta
BenchmarkNow         1262         1236   -2.06%

OpenBSD/i386 (Asus eeePC 701 with Intel Celeron M 900MHz - locked to 631MHz)
benchmark       old ns/op    new ns/op    delta
BenchmarkNow         5089         5043   -0.90%

NetBSD/i386 (VMware VM with Core i5 CPU @ 2.7GHz)
benchmark       old ns/op    new ns/op    delta
BenchmarkNow          277          278   +0.36%

NetBSD/amd64 (VMware VM with Core i5 CPU @ 2.7Ghz)
benchmark       old ns/op    new ns/op    delta
BenchmarkNow          103          105   +1.94%


Thanks Maxim Khitrov, Joel Sing, and Dave Cheney for providing benchmark data.

R=jsing, dave, rsc
CC=golang-dev
https://codereview.appspot.com/6820120
cmd/5l, cmd/6l, cmd/8l: fix function symbol generation from gcc compiled source code
For CL 6853059.

R=jsing, rsc
CC=golang-dev
https://codereview.appspot.com/6938076
A+C: Eric Milliken (individual CLA)

Generated by addca.

R=gobot
CC=golang-dev
https://codereview.appspot.com/6945079
runtime: use "mp" and "gp" instead of "m" and "g" for local variable name to avoid confusion with the global "m" and "g".

R=golang-dev, minux.ma, rsc
CC=bradfitz, golang-dev
https://codereview.appspot.com/6939064

Committer: Shenghou Ma <minux.ma@gmail.com>
cmd/go: pass gccgoflags at the end of gccgo command line, warn if user passes the wrong toolchain options

R=iant
CC=golang-dev
https://codereview.appspot.com/6940082
all: fix typos
caught by https://github.com/lyda/misspell-check.

R=golang-dev, gri
CC=golang-dev
https://codereview.appspot.com/6949072