can now forward declare across files

R=r
DELTA=15  (0 added, 15 deleted, 0 changed)
OCL=30873
CL=30880

io.ByteBuffer -> bytes.Buffer

left io.ByteBuffer stub around for now,
for protocol compiler.

R=r
OCL=30861
CL=30872

R=rsc
DELTA=185  (175 added, 10 deleted, 0 changed)
OCL=30863
CL=30871

R=r
DELTA=11  (0 added, 6 deleted, 5 changed)
OCL=30862
CL=30870

(in the same package).

allow forward method declaration to be satisfied
by implementation in another file (in the same package).
all methods must be declared in the same file
as the receiver type.

R=ken
OCL=30864
CL=30869

of structs/interfaces in other files in the package.

R=r
DELTA=12  (0 added, 12 deleted, 0 changed)
OCL=30865
CL=30868

R=r
DELTA=188  (182 added, 3 deleted, 3 changed)
OCL=30856
CL=30860

identifiers.  This is not one of the exceptions permitted by
th spec.

R=ken,rsc
DELTA=11  (11 added, 0 deleted, 0 changed)
OCL=30844
CL=30852

R=rsc
DELTA=16  (9 added, 1 deleted, 6 changed)
OCL=30846
CL=30846

R=rsc
DELTA=4  (3 added, 0 deleted, 1 changed)
OCL=30845
CL=30845

- removed smallint optimizations
- lifted raddr from 5c
- add back %R, was used in gc/* causing -g to crash
- changed naddr OREGISTER to emit D_REG instead of D_OREG

R=rsc
APPROVED=rsc
DELTA=74  (38 added, 28 deleted, 8 changed)
OCL=30799
CL=30822

Getenverror is the new name for the old routine that returns an error too.

R=rsc
DELTA=35  (7 added, 7 deleted, 21 changed)
OCL=30818
CL=30821

	type Foo struct { a int; next *Foo }
produces
	"Foo = struct { a int; next Foo }"

R=rsc
OCL=30797
CL=30820

combination.

R=rsc
APPROVED=rsc
DELTA=69  (68 added, 0 deleted, 1 changed)
OCL=30798
CL=30801

R=rsc
APPROVED=rsc
DELTA=72  (12 added, 52 deleted, 8 changed)
OCL=30748
CL=30793

not ready to be part of the standard build yet; this is just a checkpoint.

R=rsc
DELTA=361  (361 added, 0 deleted, 0 changed)
OCL=30782
CL=30785

R=rsc
APPROVED=rsc
DELTA=95  (40 added, 14 deleted, 41 changed)
OCL=30727
CL=30784

R=ken
OCL=30783
CL=30783

echo back context of call in error if likely to be useful.

For example, if os.Open("/etc/passwd", os.O_RDONLY)
fails with syscall.EPERM, it returns as the os.Error

	&PathError{
		Op: "open",
		Path: "/etc/passwd"
		Error: os.EPERM
	}

which formats as

	open /etc/passwd: permission denied

Not converted:

	datafmt
	go/...
	google/...
	regexp
	tabwriter
	template

R=r
DELTA=1153  (561 added, 156 deleted, 436 changed)
OCL=30738
CL=30781

R=ken
OCL=30760
CL=30779

R=r
DELTA=51  (4 added, 4 deleted, 43 changed)
OCL=30759
CL=30778

R=rsc
DELTA=11  (11 added, 0 deleted, 0 changed)
OCL=30774
CL=30774

package main
type t interface
type t interface{ m(map[t]bool) }
type m map[t] int

making it work without the forward declaration will require a second pass.

R=ken
OCL=30773
CL=30773

R=ken
OCL=30768
CL=30768

const foo = []int{1,2}

x.go:3: expression must be a constant

instead of

x.go:3: fatal error: gettype: addtop

R=ken
OCL=30767
CL=30767

wreck.mtv=; cat x.go
package main
var x = string.Split()
wreck.mtv=; 6g x.go
x.go:2: type string used as expression
x.go:2: undefined DOT Split on string
x.go:3: illegal types for operand: AS
	undefined
wreck.mtv=;

BUG=1938751
R=ken
OCL=30766
CL=30766

func foo(y) { }

was:
x.go:2: NONAME-y G0 u(1) a(1) l(77) x(-1000000000) is not a type

now:
x.go:2: y is not a type

R=ken
OCL=30764
CL=30764

new flag -A enables it during mkbuiltin.
avoids mysterious errors in programs
that refer to any accidentally.

R=ken
OCL=30763
CL=30763

TBR=r
OCL=30757
CL=30757

R=ken
OCL=30593
CL=30756

won't submit unless 30586 goes in.

R=r
DELTA=94  (65 added, 16 deleted, 13 changed)
OCL=30592
CL=30755

Allow indexing of string type, but not pointer to string type.
Do not allow indexing of pointer to map type.

R=r
DELTA=18  (14 added, 0 deleted, 4 changed)
OCL=30586
CL=30754

R=r
DELTA=40  (30 added, 2 deleted, 8 changed)
OCL=30742
CL=30753

R=r
DELTA=19  (0 added, 19 deleted, 0 changed)
OCL=30739
CL=30751

goroutine. arm only.

R=rsc
APPROVED=rsc
DELTA=5  (3 added, 2 deleted, 0 changed)
OCL=30644
CL=30746

R=rsc
APPROVED=rsc
DELTA=976  (164 added, 237 deleted, 575 changed)
OCL=30705
CL=30743

TBR=r
OCL=30741
CL=30741

R=r
DELTA=32  (0 added, 3 deleted, 29 changed)
OCL=30718
CL=30725

R=rsc
APPROVED=r
DELTA=131  (39 added, 10 deleted, 82 changed)
OCL=30669
CL=30723

R=r
OCL=30719
CL=30719