These are syntactical changes to better reflect the communication
operator's new status in the language.

- sending to a channel is now done via a send statement
- there is no binary communication operation anymore which
  leads to a reduction of the number of precedence levels
  from 6 to 5 (yeah!)
- small semantic change: since a send operation is not part
  of the expression syntax anymore, a <- send operator is
  binding weaker than any other operator now
- receiving from a channel is done as before via the unary
  receive expression
- communication clauses in select statement now can contain
  send statements or receive expressions

R=rsc, r, iant, ken2, gri1
CC=golang-dev
https://golang.org/cl/3973051

R=r
CC=golang-dev
https://golang.org/cl/4124047

Fixes #1453.

R=ken2
CC=golang-dev
https://golang.org/cl/4125043

R=bradfitzgo, rsc
CC=golang-dev
https://golang.org/cl/4070043

R=gri, josvazg, gri1
CC=golang-dev
https://golang.org/cl/4044047

R=r, gri1
CC=golang-dev
https://golang.org/cl/4092045

Make the error message and the needed action more obvious
when a command isn't found to obtain the source code
of a project.  Users seem to strugle with the existing
wording in practice.

R=rsc
CC=golang-dev
https://golang.org/cl/4058047

Use correct range in allocated register test.

R=rsc, ken2
CC=golang-dev
https://golang.org/cl/4073049

R=rsc
CC=golang-dev
https://golang.org/cl/4042045

The callback mechanism has been made more flexible.
Eliminated one round of argument copying in Syscall.
Faster Get/SetLastError implemented.
Added gettime for gc perf profiling.

R=rsc, brainman, mattn, rog
CC=golang-dev
https://golang.org/cl/4058046

The crypto package is added as a common place to store identifiers for
hash functions. At the moment, the rsa package has an enumeration of
hash functions and knowledge of their digest lengths. This is an
unfortunate coupling and other high level crypto packages tend to need
to duplicate this enumeration and knowledge (i.e. openpgp).

crypto pulls this code out into a common location.

It would also make sense to add similar support for ciphers to crypto,
but the problem there isn't as acute that isn't done in this change.

R=bradfitzgo, r, rsc
CC=golang-dev
https://golang.org/cl/4080046

R=rsc
CC=golang-dev
https://golang.org/cl/4105046

R=rsc, binet
CC=golang-dev
https://golang.org/cl/3921043

Test and fix case found by Robert.
Add receive inside send to tree too.

R=ken2
CC=golang-dev
https://golang.org/cl/3973052

This change fixes the import plugin so that the
defined commands are available when opening a new
Go buffer from within Vim itself.

R=adg, rsc
CC=golang-dev
https://golang.org/cl/3998053

Forcing the synchronization of 500 lines is both slower and
less precise than searching for a known sync point.
Unfortunately, though, the way to synchronize correctly is
using the grouphere instruction, which has a bug.

I've already proposed the fix to Vim, so future releases
should have this working.  We can continue using the 500 lines
syncing for now.

This change just documents the proper way to sync.

R=adg, dsymonds
CC=golang-dev
https://golang.org/cl/4029047

R=ken2
CC=golang-dev
https://golang.org/cl/4126043

R=golang-dev, nigeltao, niemeyer, r
CC=golang-dev
https://golang.org/cl/4079053

R=rsc
CC=golang-dev
https://golang.org/cl/3981049

Tweak spec to avoid ebnflint complaints.

R=gri
CC=golang-dev
https://golang.org/cl/3973050

Fixes #1455.

R=rsc
CC=golang-dev
https://golang.org/cl/4079055

R=rsc
CC=golang-dev
https://golang.org/cl/4105044

Previously, group numbers were updated while being read,
sometimes leading to inconsistencies.

R=gri, gri1
CC=golang-dev
https://golang.org/cl/4121045

R=rsc
CC=golang-dev
https://golang.org/cl/4029048

R=rsc
CC=golang-dev
https://golang.org/cl/4017045

If there were warnings or errors in the user code,
cgo would print the first error from gcc and then stop,
which is not helpful.
This CL makes cgo ignore errors from user code
in the first pass - they will be shown later.
It also prints errors from user preamble code
with the correct line numbers.
(Also fixed misleading usage message).

R=iant, rsc
CC=golang-dev
https://golang.org/cl/4082047

R=rsc
CC=golang-dev
https://golang.org/cl/4079049

R=r
CC=golang-dev
https://golang.org/cl/4121042

The "all:" target is the default for running gomake
by hand, but it is not used during the build.
The build runs make install and make test.

Save the build of maketables for the test phase
so that the packages it needs will have been
installed already.

R=r, r2
CC=golang-dev
https://golang.org/cl/4121043

R=rsc, mattn
CC=golang-dev
https://golang.org/cl/4047047

R=r
CC=golang-dev
https://golang.org/cl/4119048

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/4119047

one bug fixed,
probably more will be revealed

R=r
CC=golang-dev
https://golang.org/cl/4126044

R=r
CC=golang-dev
https://golang.org/cl/4073046

R=ken2
CC=golang-dev
https://golang.org/cl/4004045

R=r
CC=golang-dev
https://golang.org/cl/4004044

R=golang-dev, agl1
CC=golang-dev
https://golang.org/cl/4079051

- fixed length of amd64 .data pe section
  (don't need to include non-initialised data)

- use correct oh/oh64 variable when updating
  data directory in addexports

- simplify and cleanup

R=vcc, rsc
CC=golang-dev
https://golang.org/cl/4106044

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/4073043

R=rsc
CC=golang-dev
https://golang.org/cl/4124041