Fixes #2918.

TBR=golang-dev
CC=golang-dev
https://golang.org/cl/5639062

- convert from nil pointers to the nil interface{}
- dereference non-nil pointers
- convert from nil interface{}s to nil pointers
- allocate pointers for non-nil interface{}s
- tests for all of the above

R=golang-dev, bradfitz, rsc, rogpeppe
CC=golang-dev
https://golang.org/cl/5630052

Fixes #2875

R=golang-dev, r, rsc
CC=golang-dev
https://golang.org/cl/5641052

R=golang-dev, r, iant
CC=golang-dev
https://golang.org/cl/5641051

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/5646049

Add Expand, ExpandString for access to the substitution functionality.

Fixes #2736.

R=r, bradfitz, r, rogpeppe, n13m3y3r
CC=golang-dev
https://golang.org/cl/5638046

encoding/xml: handle time.Time as recognized type

The long term plan is to define an interface that time.Time
can implement and that encoding/xml can call, but we are
not going to try to define that interface before Go 1.
Instead, special-case time.Time in package xml, because
it is such a fundamental type, as a stop-gap.
The eventual methods will behave this way.

Fixes #2793.

R=golang-dev, r, r, n13m3y3r
CC=golang-dev
https://golang.org/cl/5634051

Fixes #2642.

R=remyoudompheng, r, r
CC=golang-dev
https://golang.org/cl/5639052

Fixes #2851.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5644048

It appears to want a * on an indirect function call (assembly language)

TBR=rsc

R=golang-dev
CC=golang-dev
https://golang.org/cl/5643054

TBR=rsc

R=golang-dev
CC=golang-dev
https://golang.org/cl/5647049

This also changes the behavior of attribute marshalling so
that strings and byte slices are marshalled even if empty.
The omitempty flag may be used to obtain the previous behavior.

Fixes #2899.

R=rsc
CC=golang-dev
https://golang.org/cl/5645050

R=golang-dev, nigeltao
CC=golang-dev
https://golang.org/cl/5645052

R=golang-dev, dsymonds, r
CC=golang-dev
https://golang.org/cl/5615056

Fixes #2835.

R=golang-dev, n13m3y3r, r, bradfitz
CC=golang-dev
https://golang.org/cl/5645051

Fixes #2847.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5641050

to help debug Issue 2651

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/5644049

The function has a bizarre signature: it was the only public function there
that exposed the reflect package. Also, its definition is peculiar and hard to
explain. It doesn't merit being exported.

This is an API change but really, it should never have been exported and
it's certain very few programs will depend on it: it's too weird.

Fixes #2846.

R=golang-dev, gri, bradfitz
CC=golang-dev
https://golang.org/cl/5639054

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5626045

It complicates the interface unnecessarily.
Document this in go1.html.
Also update the go/doc Makefile.

Fixes #2836.

R=golang-dev, gri, bradfitz
CC=golang-dev
https://golang.org/cl/5642054

Fixes #2853

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5642056

Also simplify the tests.

Fixes #2849.

R=golang-dev, bradfitz, r
CC=golang-dev
https://golang.org/cl/5643045

R=r
CC=golang-dev
https://golang.org/cl/5636045

Fixes #2862.

R=golang-dev, n13m3y3r, iant
CC=golang-dev
https://golang.org/cl/5646048

It's disabled and unreproducible.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5642053

Be careful when printing line comments with incorrect
position information. Maintain additional state
impliedSemi: when set, a comment containing a newline
would imply a semicolon and thus placement must be
delayed.

Precompute state information pertaining to the next
comment for faster checks (the printer is marginally
faster now despite additional checks for each comment).

No effect on existing src, misc sources.

Fixes #1505.

R=rsc
CC=golang-dev
https://golang.org/cl/5598054

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/5643050

Fixes #2902.

TBR=golang-dev
CC=golang-dev
https://golang.org/cl/5641047

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5639046

Also bring the names in doc.go in line with the source.
More radical resolutions are possible but require substantial internal
changes for very little benefit. Fixing it this way lets us keep the
embedding, which has a huge simplifying effect, and guarantees
binary compatibility.

Fixes #2848.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5644045

Fixes #2850.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5645043

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