align the output args separately from the input args,
change cgo2c to insert the necessary padding
when the two arg lists are concatenated in the c
translation.

for example, there is a runtime

	func indexstring(s string, i int32) (b byte)

right now in 6g those arguments are aligned in one
struct with s at offset 0, i at 16, and b at 20.
soon the b byte will be in its own struct and structs
are 8 aligned, so it will be b at 24.

right now cgo2c generates:

	void indexstring(string s, int32 i, byte b)

this CL makes it generate, in --6g mode:

	void indexstring(string s, int32 i, uint32, byte b)

this is valid 6c input, although not valid gcc input.
(the code is being generated for 6c only anyway.)

also, allow C code to be mixed in among the Go funcs.
every instance of the token `func' is expected to start
a new go func.

R=iant
DELTA=145  (118 added, 0 deleted, 27 changed)
OCL=30949
CL=30963

R=rsc
DELTA=897  (728 added, 14 deleted, 155 changed)
OCL=30955
CL=30955

R=rsc
DELTA=172  (40 added, 6 deleted, 126 changed)
OCL=30941
CL=30944

R=rsc
DELTA=610  (597 added, 5 deleted, 8 changed)
OCL=30934
CL=30939

R=r
DELTA=25  (0 added, 15 deleted, 10 changed)
OCL=30892
CL=30892

R=ken
OCL=30889
CL=30889

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