Also allow multiple invalid import statements in a
single file.

Fixes #3021. The changes to go/parser and the
language specifcation have already been committed.

R=rsc, gri
CC=golang-dev
https://golang.org/cl/5672084

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5697043

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5696048

R=golang-dev, r, adg
CC=golang-dev
https://golang.org/cl/5683076

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5697051

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5696054

Functions are equal iff they are both nil.

Fixes #3122.

R=golang-dev, dsymonds, rsc
CC=golang-dev
https://golang.org/cl/5693057

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5694065

signal.test binary passes on my phone; should fix builder

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5694064

R=ken2
CC=golang-dev, lvd
https://golang.org/cl/5693056

Now they actually test again instead of just setting iota to zero.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5700058

We were not aligning the code size,
so read-only data, which follows in the same
segment, could be arbitrarily misaligned.

Fixes #2506.

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/5693055

Turns out U+FFFD is a graphic character too.

http://play.golang.org/p/YblCfKAfko

R=gri
CC=golang-dev
https://golang.org/cl/5699052

Avoids global array buffer overflows if they are
indexed using some of the values between NTYPE
and NALLTYPE.  It is entirely likely that not all of these
are necessary, but this is the C compiler and not worth
worrying much about.  This change takes up only a
few more bytes of memory and makes the behavior
deterministic.

Fixes #3078.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5693052

Fixes #3113.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5698056

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5694063

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5699060

Also reformat the "go fix" references to make them look better by using the non-CW space.

Fixes #3087.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5695057

To find test files with legacy headers.

We can remove this flag once everything is converted.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5694060

R=adg
CC=golang-dev
https://golang.org/cl/5699057

R=golang-dev, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/5688067

R=golang-dev, bradfitz, r
CC=golang-dev
https://golang.org/cl/5700056

Fixes #3094.

R=golang-dev, rsc, nigeltao
CC=golang-dev
https://golang.org/cl/5687065

The rename ones needed redoing.

R=golang-dev, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/5698054

R=adg, rsc
CC=golang-dev
https://golang.org/cl/5695054

Fixes #1226.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5694052

    While we are at it, also update some comments.
    Tested on Linux/ARM builder.

R=rsc, golang-dev
CC=golang-dev
https://golang.org/cl/5696047

Fixes #3112.

R=golang-dev, 0xe2.0x9a.0x9b, ality, rsc, rsc
CC=golang-dev
https://golang.org/cl/5700044

R=rsc
CC=golang-dev
https://golang.org/cl/5698052

R=golang-dev, bradfitz, dsymonds, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/5700043

R=gri
CC=golang-dev
https://golang.org/cl/5697047

Fixes #3101 (darwin).

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5693044

Fixes #3101 (Linux).

R=golang-dev, bradfitz, minux.ma
CC=golang-dev
https://golang.org/cl/5696043

Alternatively, we could expand the ewidth array
in [568]c/txt.c to have NALLTYPES elements and
give all types above NTYPE a width of -1.

I don't think it's worth it since TDOT and TOLD
are the only two type values above NTYPE that
are passed to typ:

$ /tmp/cctypes
cc/dcl.c:683: 			t->down = typ(TOLD, T);
cc/dcl.c:919: 		return typ(TDOT, T);
$

Fixes #3063.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5694047

Replaced /*-style comments with line comments;
there are two many *'s already in those lines.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5699051

Although Intel considers the three-argument form of IMUL to be a
variant of IMUL, I couldn't make 6l able to differentiate it without
huge changes, so I called it IMUL3.

R=rsc
CC=golang-dev
https://golang.org/cl/5686055

R=rsc, r, r, adg
CC=golang-dev
https://golang.org/cl/5688074

R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/5674112

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/5695046

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/5698044