The m->cret word holds the C return value when returning
across a stack split boundary.  It was not being cleared after
use, which means that the return value (if a C function)
or else the value of AX/R0 at the time of the last stack unsplit
was being kept alive longer than necessary.  Clear it.

I think the effect here should be very small, but worth fixing
anyway.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5677092

Fixes #3065

R=golang-dev, dsymonds, rsc
CC=golang-dev
https://golang.org/cl/5675094

R=ken2
CC=golang-dev
https://golang.org/cl/5674108

Delete Alloc, Free, Lookup, Semacquire, Semrelease

Fixes #2955.

R=golang-dev, r, bradfitz
CC=golang-dev
https://golang.org/cl/5675093

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5656103

I'm sure I wrote these before but they've disappeared.

R=golang-dev, bradfitz, r
CC=golang-dev
https://golang.org/cl/5673100

Very few of the compiler regression tests include a comment
saying waht they do. Many are obvious, some are anything but.
I've started with a-c in the top directory. More will follow once
we agree on the approach, correctness, and thoroughness here.
zerodivide.go sneaked in too.

R=rsc, r
CC=golang-dev
https://golang.org/cl/5656100

R=golang-dev, ken2
CC=golang-dev
https://golang.org/cl/5674098

Fixes #2964.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5656101

Fixes #3067.

R=golang-dev, rsc, rsc
CC=golang-dev
https://golang.org/cl/5656098

Generated by lib/time/update.bash.

R=bradfitz
CC=golang-dev
https://golang.org/cl/5676096

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5674104

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5674105

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5675092

Apply sed with:

1s,^// $G $D/$F.go && $L $F.$A && ./$A.out || echo.*,// run,
1s,^// $G $D/$F.go || echo.*,// compile,

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5656099

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5676094

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5677084

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5673080

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5673090

R=golang-dev, bradfitz, r, r
CC=golang-dev
https://golang.org/cl/5676090

R=golang-dev, adg, r
CC=golang-dev
https://golang.org/cl/5649068

Fixes #3053.

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/5656094

Because bug040.go was ignoring all error messages, the fact
that it got an error about fuction main was being ignored.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5675085

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5673089

R=r, bradfitz, r, adg
CC=golang-dev
https://golang.org/cl/5675076

When we build the encode engine for a recursive type, we
mustn't disregard the indirections or we can try to reuse an
engine at the wrong indirection level.

Fixes #3026.

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/5675087

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5671090

Fix by setting the element type if we discover it's zero while building.
We could have fixed this better with foresight by doing the id setting in a
different sequence, but doing that now would break binary compatibility.

Fixes #2995.

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/5675083

R=golang-dev, gri, r
CC=golang-dev
https://golang.org/cl/5676071

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5673087

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5676084

I am making a unilateral decision here. I could also settle for returning 0,
as long it's documented, but I argue that it's equivalent to an index
out of bounds.

Fixes #2892.

R=golang-dev, dsymonds, rsc
CC=golang-dev
https://golang.org/cl/5676079

R=golang-dev, r, gri
CC=golang-dev
https://golang.org/cl/5675081

Fixes #3048.

R=rsc
CC=golang-dev
https://golang.org/cl/5672081

Fixes #2989.

R=ken2
CC=golang-dev
https://golang.org/cl/5674091

Fixes #3061.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5656089

Fixes #3041.

R=rsc
CC=golang-dev
https://golang.org/cl/5671087

R=r
CC=golang-dev
https://golang.org/cl/5675074

R=r
CC=golang-dev
https://golang.org/cl/5676074

files moved from misc/windows, bash packager file replaced with Windows batch file

R=golang-dev, alex.brainman, rsc
CC=golang-dev
https://golang.org/cl/5677074