Drop reference to "machine type."  Specify that integer
overflow must be an error.  Drop requirement that exponent
must be 128 bits--that's a lot.  Clarify that floating point
expressions may be rounded, including intermediate values.

This is a reworking of https://golang.org/cl/5577068/ .

Fixes #2789.

R=r, rsc, r, gri, ken, ken, iant
CC=golang-dev, remyoudompheng
https://golang.org/cl/5655049

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5645099

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5650076

R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/5650077

Restore package os/signal, with new API:
Notify replaces Incoming, allowing clients
to ask for certain signals only.  Also, signals
go to everyone who asks, not just one client.

This could plausibly move into package os now
that there are no magic side effects as a result
of the import.

Update runtime for new API: move common Unix
signal handling code into signal_unix.c.
(It's so easy to do this now that we don't have
to edit Makefiles!)

Tested on darwin,linux 386,amd64.

Fixes #1266.

R=r, dsymonds, bradfitz, iant, borman
CC=golang-dev
https://golang.org/cl/3749041

1) Remove the Reset() member in crypto/aes and crypto/des (and
   document the change).
2) Turn several empty error structures into vars. Any remaining error
   structures are either non-empty, or will probably become so in the
   future.
3) Implement SetWriteDeadline for TLS sockets. At the moment, the TLS
   status cannot be reused after a Write error, which is probably fine
   for most uses.
4) Make crypto/aes and crypto/des return a cipher.Block.

R=rsc, r
CC=golang-dev
https://golang.org/cl/5625045

one trie lookup per rune is needed. See forminfo.go for a description
of the new format.  Also included leading and trailing canonical
combining class in decomposition information.  This will often avoid
additional trie lookups.

R=r, r
CC=golang-dev
https://golang.org/cl/5616071

Thanks to Aaron Kemp for noticing.

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/5645097

This is not the finished product,
but a good checkpoint from which to
proceed with further development.

R=golang-dev, dsymonds, r
CC=golang-dev
https://golang.org/cl/5571061

R=golang-dev, bradfitz, iant
CC=golang-dev
https://golang.org/cl/5639064

8g/cgen.c
        print format type mismatch

8l/asm.c
        resoff set and not used

gc/pgen.c
        misleading comparison INT > 0x80000000

gc/reflect.c
        dalgsym must be static to match forward declaration

gc/subr.c
        assumed_equal set and not used
        hashmem's second argument is not used

gc/walk.c
        duplicated (unreachable) code

R=rsc
CC=golang-dev
https://golang.org/cl/5651079

hammerCompareAndSwapPointer64 was only passing on
little-endian systems.  hammerCompareAndSwapPointer32 was
writing 8 bytes to a uint32 value on the heap.

R=rsc, dvyukov
CC=golang-dev
https://golang.org/cl/5654065

It did in fact break on the darwin/386 builder.
Will investigate later; reopened issue 2917.

R=golang-dev
CC=golang-dev
https://golang.org/cl/5654070

You could argue for changing all the others, but
Linux is outvoted, and the only time it matters
is when newfd==-1, in which case you can call Dup.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5650073

Fixes #2776.

There was a previous attempt at CL 5592043 but that
seems to have stalled.  This one is simpler, and more up to date
(correct handling of spdy, for example).

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5645091

The Date-Modified header truncates sub-second precision, so
use mtime < t+1s instead of mtime <= t to check for unmodified.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5655052

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5652078

Sorry, Mercurial failed me.

TBR=r, dsymonds
CC=golang-dev
https://golang.org/cl/5649080

Among other things, this avoids putting a testing.go:nnn:
prefix on every line of the stack trace.

R=golang-dev, r, dsymonds, r
CC=golang-dev
https://golang.org/cl/5651081

unsafe: delete Typeof, Reflect, Unreflect, New, NewArray

Part of issue 2955 and issue 2968.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5650069

Fixes #2690.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5650071

Cannot reproduce the failure locally,
but add explicit test in case some other
machine can.

Fixes #2917 (for now).

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5651071

Fixes #2943.

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/5649079

Fixes #2919.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5645089

I thought that -timeout was per-test, but it is for the
whole program execution, so cmd/go can adjust its timer
(also for whole program execution) accordingly.

Fixes #2993.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5650070

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/5650068

Fixes #2365.

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/5653070

Also, echo cmd/dist during bootstrap build
Makes that phase look like all the others.

Fixes #2908.

R=golang-dev, alex.brainman, bradfitz
CC=golang-dev
https://golang.org/cl/5655065

Fixes #2916.

R=golang-dev, remyoudompheng, r, rsc
CC=golang-dev
https://golang.org/cl/5652064

Fixes #2830 (again).

R=rsc
CC=golang-dev
https://golang.org/cl/5651083

The paragraph describing the ellipses presents the horizontal ellipsis
in two different fonts and at least on my screen they look too different.
Switch to a consistent rendering.

Of small steps are great journeys undertaken.

R=golang-dev, rsc, dsymonds, gri
CC=golang-dev
https://golang.org/cl/5650055

so they don't collide with names like #Index.
Fixes #2970.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5655066

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5649074

R=golang-dev, bsiegert, r
CC=golang-dev
https://golang.org/cl/5643068

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/5645092

The example was fixed; the simplifying rewrite was missed.

R=golang-dev
CC=golang-dev
https://golang.org/cl/5651080

R=golang-dev, n13m3y3r
CC=golang-dev
https://golang.org/cl/5649072

R=golang-dev, alex.brainman
CC=golang-dev
https://golang.org/cl/5653066

It doesn't work anymore and it's not used.

R=golang-dev, mikioh.mikioh
CC=golang-dev
https://golang.org/cl/5652073

R=golang-dev, r, r
CC=golang-dev
https://golang.org/cl/5654062