add "extern register" support to 8c.
extern register means allocate in the FS-relative segment.

make 8l generate segmented stack checks.

R=ken
OCL=26600
CL=26606

was applying wrong waste check,
resulting in many more size classes
than necessary.

R=r
DELTA=2  (0 added, 0 deleted, 2 changed)
OCL=26602
CL=26605

R=ken,rsc
DELTA=30  (30 added, 0 deleted, 0 changed)
OCL=26599
CL=26604

R=ken
OCL=26584
CL=26589

also use thechar, to make copy/paste easier.

R=ken
OCL=26583
CL=26588

R=ken
OCL=26581
CL=26587

also fix multiple-evaluation bug in range over arrays.

R=ken
OCL=26576
CL=26576

bug090.go:41:6: error: floating point constant truncated to integer
bug090.go:32:6: error: floating point constant truncated to integer
bug090.go:34:14: error: floating point constant truncated to integer
bug090.go:37:5: error: incompatible types in assignment
bug090.go:40:5: error: incompatible types in assignment

R=rsc
DELTA=2  (0 added, 0 deleted, 2 changed)
OCL=26564
CL=26574

const1.go:23:13: error: integer constant overflow
const1.go:25:13: error: integer constant overflow
const1.go:26:14: error: integer constant overflow
const1.go:27:18: error: integer constant overflow
const1.go:28:19: error: integer constant overflow
const1.go:29:16: error: integer constant overflow
const1.go:29:25: error: integer constant overflow
const1.go:30:13: error: integer constant overflow
const1.go:33:14: error: integer constant overflow
const1.go:34:14: error: integer constant overflow
const1.go:36:22: error: integer constant overflow
const1.go:37:7: error: integer constant overflow
const1.go:38:8: error: integer constant overflow
const1.go:39:7: error: integer constant overflow
const1.go:40:7: error: integer constant overflow
const1.go:41:8: error: integer constant overflow
const1.go:44:23: error: integer constant overflow
const1.go:46:13: error: integer constant overflow
const1.go:47:24: error: integer constant overflow
const1.go:48:24: error: integer constant overflow
const1.go:49:22: error: integer constant overflow
const1.go:51:23: error: integer constant overflow
const1.go:52:19: error: division by zero
const1.go:58:11: error: division by zero
const1.go:43:17: error: integer constant overflow
const1.go:45:13: error: integer constant overflow
const1.go:55:19: error: floating point overflow
const1.go:56:28: error: floating point overflow
const1.go:57:11: error: floating point overflow
const1.go:64:2: error: argument 0 has wrong type
const1.go:65:2: error: argument 0 has wrong type
const1.go:66:2: error: argument 0 has wrong type
const1.go:68:2: error: argument 0 has wrong type
const1.go:69:2: error: argument 0 has wrong type
const1.go:70:4: error: floating point constant truncated to integer
const1.go:72:2: error: argument 0 has wrong type
const1.go:73:2: error: argument 0 has wrong type
const1.go:74:2: error: argument 0 has wrong type

R=rsc
DELTA=34  (0 added, 0 deleted, 34 changed)
OCL=26560
CL=26560

R=r
DELTA=16  (5 added, 1 deleted, 10 changed)
OCL=26530
CL=26543

address operators, to follow.

R=rsc
DELTA=11  (10 added, 0 deleted, 1 changed)
OCL=26529
CL=26532

R=rsc,gri
DELTA=97  (26 added, 42 deleted, 29 changed)
OCL=26436
CL=26527

BUG=1722502
R=ken
OCL=26526
CL=26526

R=rsc
APPROVED=rsc
DELTA=22  (9 added, 6 deleted, 7 changed)
OCL=26498
CL=26500

R=rsc,gri
DELTA=103  (36 added, 33 deleted, 34 changed)
OCL=26442
CL=26491

R=rsc
DELTA=76  (0 added, 63 deleted, 13 changed)
OCL=26439
CL=26490

R=r
OCL=26480
CL=26480

R=rsc
OCL=26438
CL=26438

R=rsc
DELTA=169  (169 added, 0 deleted, 0 changed)
OCL=26433
CL=26437

R=r
OCL=26434
CL=26434

- first part of AST cleaned up and documented
- tons of related cleanups and adjustments

R=r
OCL=26430
CL=26430

R=rsc,gri
DELTA=107  (90 added, 1 deleted, 16 changed)
OCL=26420
CL=26427

new feature 'case nil:' in type switch
will match iff the interface is nil.

R=r
OCL=26404
CL=26404

also make the default input for makehtml be go_tutorial.txt.

R=rsc
DELTA=176  (58 added, 58 deleted, 60 changed)
OCL=26374
CL=26374

const2.go:7:9: error: expected '='

Uses '.' to recognize the quotation marks, as the actual
characters printed depend on the user's locale.

R=rsc
DELTA=1  (0 added, 0 deleted, 1 changed)
OCL=26360
CL=26373

label redefinition error.

R=gri
DELTA=6  (0 added, 0 deleted, 6 changed)
OCL=26357
CL=26372

- use explicit expression lists instead of binary trees to represent lists of the form a, b, c
(per discussion w/ Russ)
- use explicit nodes for various language constructs for better readability
- various adjustments in parsing and printing

next steps:
- clean up AST fully so it can be checked in as library

R=r
OCL=26371
CL=26371

- no syntactic or semantic change

R=r
DELTA=45  (24 added, 18 deleted, 3 changed)
OCL=26349
CL=26368

to allow room for type hash
needed for log-time type switch.

R=r
OCL=26354
CL=26354

R=rsc
DELTA=14  (12 added, 0 deleted, 2 changed)
OCL=26278
CL=26348

R=rsc
DELTA=19  (19 added, 0 deleted, 0 changed)
OCL=26284
CL=26336

- various parser fixes to match updated spec (&&, &^=, label decls, const decls)
- using html template for directory and error page in doc server
- show compile errors inplace in the source
- cleanups

R=rsc
OCL=26287
CL=26287

R=r
OCL=26281
CL=26285

R=rsc
APPROVED=rsc
DELTA=19042  (19042 added, 0 deleted, 0 changed)
OCL=26268
CL=26270

R=rsc
DELTA=18  (18 added, 0 deleted, 0 changed)
OCL=26266
CL=26266

close two more bugs.

R=ken
OCL=26226
CL=26226

go_spec.html: document const type propagation

R=ken
OCL=26223
CL=26225

various bug fixes and tests involving constants.

test/const1.go is the major new test case.

R=ken
OCL=26216
CL=26224

OCL=26222
CL=26222

R=rsc
OCL=26220
CL=26220