removal and typesigs and strings.

Also added new header support to 5c/5a/5l.

R=rsc
APPROVED=rsc
DELTA=98  (66 added, 10 deleted, 22 changed)
OCL=30103
CL=30123

R=rsc
APPROVED=rsc
DELTA=4  (0 added, 4 deleted, 0 changed)
OCL=30110
CL=30112

R=rsc
APPROVED=rsc
DELTA=392  (386 added, 2 deleted, 4 changed)
OCL=29963
CL=30107

TBR=r
OCL=30106
CL=30106

tests: all.bash passes, gobuild still works, godoc still works.

R=rsc
OCL=30096
CL=30102

needs to dereference the base pointer to make
sure it catches nil.

R=r,ken
DELTA=21  (21 added, 0 deleted, 0 changed)
OCL=30083
CL=30101

R=rsc
APPROVED=rsc
DELTA=371  (370 added, 0 deleted, 1 changed)
OCL=30029
CL=30084

so 64-bit args like the offset in Seek were being
mishandled.  fix.

R=dsymonds
DELTA=1269  (645 added, 611 deleted, 13 changed)
OCL=30082
CL=30082

R=rsc
APPROVED=rsc
DELTA=245  (167 added, 63 deleted, 15 changed)
OCL=30039
CL=30081

R=rsc
DELTA=1  (0 added, 0 deleted, 1 changed)
OCL=30080
CL=30080

- support debug/sync (if automatic sync is enabled in the first place)
- removed debug/restart feature

R=rsc
DELTA=97  (37 added, 27 deleted, 33 changed)
OCL=30068
CL=30079

R=gri
DELTA=14  (6 added, 4 deleted, 4 changed)
OCL=30072
CL=30074

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R=presotto
APPROVED=p
DELTA=50  (50 added, 0 deleted, 0 changed)
OCL=30056
CL=30061

R=gri
DELTA=2  (2 added, 0 deleted, 0 changed)
OCL=30058
CL=30060

- added corresponding test case

R=rsc
DELTA=10  (7 added, 1 deleted, 2 changed)
OCL=30055
CL=30059

fix darwin interrupt bug (race with SIGCHLD).

R=gri
DELTA=46  (40 added, 0 deleted, 6 changed)
OCL=30052
CL=30057

R=rsc
DELTA=31  (6 added, 8 deleted, 17 changed)
OCL=30046
CL=30051

R=rsc
APPROVED=rsc
DELTA=2  (1 added, 0 deleted, 1 changed)
OCL=30043
CL=30043

hand-edited files.

R=r
DELTA=125  (77 added, 16 deleted, 32 changed)
OCL=30001
CL=30008

only automatic g4 mv here.

R=r
OCL=30002
CL=30007

R=dsymonds
DELTA=559  (559 added, 0 deleted, 0 changed)
OCL=29993
CL=30005

R=dsymonds
DELTA=858  (858 added, 0 deleted, 0 changed)
OCL=29992
CL=30004

to expose new CloseWithError methods.

R=r
DELTA=161  (72 added, 15 deleted, 74 changed)
OCL=29980
CL=30003

needs cleanup, optimizer,
but all.bash works.

R=ken
OCL=29974
CL=30000

R=ken
OCL=29989
CL=29999

instead of having to double the type and statement grammars.

R=ken
OCL=29987
CL=29998

R=ken
OCL=29984
CL=29997

TBR=r
OCL=29991
CL=29994

R=rsc
APPROVED=rsc
DELTA=45  (37 added, 1 deleted, 7 changed)
OCL=29964
CL=29990

R=r
DELTA=2  (0 added, 0 deleted, 2 changed)
OCL=29986
CL=29988

  * no longer distinguishes const, var, type, package names.
  * all the predefined names are not tokens anymore.

R=ken
OCL=29326
CL=29985

R=gri
DELTA=1  (0 added, 0 deleted, 1 changed)
OCL=29971
CL=29975

R=rsc
DELTA=1  (1 added, 0 deleted, 0 changed)
OCL=29970
CL=29973

R=ken
OCL=29972
CL=29972

TBR=rsc
DELTA=1  (0 added, 0 deleted, 1 changed)
OCL=29969
CL=29969

(on plan 9 cc calls it log2, but that conflicts here.)
the difference is that xlog2 returns -1 on non powers of 2.
8c was rewriting /10 into /8.

R=ken
OCL=29968
CL=29968

 * use new Make.$GOARCH files in gobuild.
 * rename 6ar to arch-generic gopack.
 * place objects in $GOROOT/pkg/$GOOS_$GOARCH
   (makes cross-compiling easier, and no one
   ever types these paths by hand anyway).

R=r
DELTA=29  (6 added, 8 deleted, 15 changed)
OCL=29923
CL=29967

R=r
DELTA=761  (1 added, 433 deleted, 327 changed)
OCL=29927
CL=29966

- don't show p4 sync output if -verbose is not set

R=rsc
DELTA=25  (5 added, 15 deleted, 5 changed)
OCL=29962
CL=29962

R=rsc
DELTA=1  (0 added, 0 deleted, 1 changed)
OCL=29961
CL=29961