Updates #2836.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5639045

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5639043

Commands such as "dist version > VERSION" will cause
the shell to create an empty VERSION file and set dist's
stdout to its fd. dist in turn looks at VERSION and uses
its content if available, which is empty at this point.

Fix that by ignoring VERSION if it's empty.

Also prevent cmdversion from running findgoversion a
second time. It was already loaded by init.

R=adg, gustavo, rsc
CC=golang-dev
https://golang.org/cl/5639044

R=r
CC=golang-dev
https://golang.org/cl/5644044

R=dsymonds
CC=golang-dev
https://golang.org/cl/5636053

R=golang-dev, rsc
CC=bradfitz, golang-dev, mikioh.mikioh
https://golang.org/cl/5616066

I hate symlinks.
Fixes #2787.

R=golang-dev, dsymonds, rsc
CC=golang-dev
https://golang.org/cl/5638043

There's no reason to set GOROOT as the tools will have the path baked
into it with GOROOT_FINAL.

R=bradfitz, bytbox, gustavo, rsc
CC=golang-dev
https://golang.org/cl/5576064

Fixes #2534.

R=golang-dev, dsymonds, bradfitz
CC=golang-dev
https://golang.org/cl/5635051

This time for sure.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5634046

Signatures of fatalf and error_ helpers have been matched for
consistency.
Fixes #1800.

R=rsc
CC=golang-dev, remy
https://golang.org/cl/5593049

R=golang-dev, n13m3y3r
CC=golang-dev
https://golang.org/cl/5634048

Specifically, remove simply where it is claiming that the
code or the action to be carried out is simple, since the
reader might disagree.

R=golang-dev, bradfitz, gri
CC=golang-dev
https://golang.org/cl/5637048

As a convenience to people working on the tools,
leave Makefiles that invoke the go dist tool appropriately.
They are not used during the build.

R=golang-dev, bradfitz, n13m3y3r, gustavo
CC=golang-dev
https://golang.org/cl/5636050

This is the same heuristic that build.ScanDir uses.
It avoids considering 'resource fork' files on OS X;
the resource for x.go is ._x.go.

R=gri
CC=golang-dev
https://golang.org/cl/5616073

Unexports runtime.MemStats and rename MemStatsType to MemStats.
The new accessor requires passing a pointer to a user-allocated
MemStats structure.

Fixes #2572.

R=bradfitz, rsc, bradfitz, gustavo
CC=golang-dev, remy
https://golang.org/cl/5616072

See thread http://goo.gl/7zzzU for background.

R=rsc
CC=golang-dev
https://golang.org/cl/5624051

        Also modify runtime/asm_386.s to use it.

R=rsc
CC=golang-dev
https://golang.org/cl/5634043

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5629055

        also made generated scripts act more like running go clean itself

R=golang-dev
CC=golang-dev, rsc
https://golang.org/cl/5624049

Fixes #2827.

R=ken2
CC=golang-dev
https://golang.org/cl/5638045

Fixes #2872

R=andybalholm, rsc
CC=golang-dev
https://golang.org/cl/5608056

Passing the CGO_CFLAGS to cgo is required to make alternative include
directories work when building a cgo project.

R=rsc
CC=golang-dev
https://golang.org/cl/5635048

Multiplying by the low 32 bits was a bad idea
no matter what, but it was a particularly unfortunate
choice because those bits are 0 for small integer values.

Fixes #2883.

R=ken2
CC=golang-dev
https://golang.org/cl/5634047

Right now, GOTRACEBACK=0 means do not show any stack traces.
Unset means the default behavior (declutter by hiding runtime routines).

This CL makes GOTRACEBACK=2 mean include the runtime routines.
It avoids having to recompile the runtime when you want to see
the runtime in the tracebacks.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5633050

Fixes #2877

R=rsc
CC=golang-dev
https://golang.org/cl/5637047

Fixes #2821.

R=rsc
CC=golang-dev
https://golang.org/cl/5606061

Zip files may actually store symlinks, and that's represented
as a file with unix flag S_IFLNK and with its data containing
the symlink target name.

The other flags are being supported too. Now that the os package
has the full range of flags in a system agnostic manner, there's
no reason to discard that information.

R=golang-dev, adg, rogpeppe
CC=golang-dev
https://golang.org/cl/5624048

As pointed out in the discussion around 2678.

R=rsc
CC=golang-dev
https://golang.org/cl/5534077

since the real type is not inferred.
Fixes #2885.

R=golang-dev, dsymonds, bradfitz
CC=golang-dev
https://golang.org/cl/5633045

R=golang-dev
TBR=adg
CC=golang-dev, patrick
https://golang.org/cl/5616070

- fix documentation for NewBuffer and NewBufferString
- document and implement behavior of Truncate on invalid lengths

Fixes #2837.

R=rsc, adg
CC=golang-dev
https://golang.org/cl/5637044

- eliminate local Error type (a historical artifact)
- fix documentation of CopyN
- fix documentation of WriteString
Fixes #2859.

R=rsc, bradfitz
CC=golang-dev
https://golang.org/cl/5636046

      This fix makes the goFilesPackage helper function print the errors from
      package imports and exit similar to how the packagesForBuild function does.

      Without this change, when invoking "go build *.go" with, for example,
      an old import path, the following stack trace is generated:

      panic: runtime error: invalid memory address or nil pointer dereference

      goroutine 1 [running]:
      go/build.(*Tree).PkgDir(...)
              /opt/go/src/pkg/go/build/path.go:52 +0xfb
      main.(*builder).action(...)
              /opt/go/src/cmd/go/build.go:327 +0xb8
      main.(*builder).action(...)
              /opt/go/src/cmd/go/build.go:335 +0x208
      main.runBuild(...)
              /opt/go/src/cmd/go/build.go:129 +0x386
      main.main()
              /opt/go/src/cmd/go/main.go:126 +0x2d8

Fixes #2865.

R=rsc, dvyukov, r
CC=golang-dev
https://golang.org/cl/5624052

The practice encourages people to think this is the way to
create a bytes.Buffer when new(bytes.Buffer) or
just var buf bytes.Buffer work fine.
(html/token.go was missing the point altogether.)

R=golang-dev, bradfitz, r
CC=golang-dev
https://golang.org/cl/5637043

Fixes #2689.

R=r
CC=golang-dev
https://golang.org/cl/5616063

R=r
CC=golang-dev
https://golang.org/cl/5633044

Fixes #2857.

R=r, adg
CC=golang-dev
https://golang.org/cl/5635046

R=golang-dev, alex.brainman
CC=golang-dev
https://golang.org/cl/5631051

R=golang-dev, ality
CC=golang-dev
https://golang.org/cl/5636044