the last bit of data.

add a new iotest.DataErrReader for tests

R=r
DELTA=93  (41 added, 31 deleted, 21 changed)
OCL=33897
CL=33915

R=r
OCL=33913
CL=33913

R=gri
DELTA=105  (77 added, 23 deleted, 5 changed)
OCL=33890
CL=33910

after this CL, two more to come:
	1) add an exhaustive test, probably as a variant of maketables
	2) add ToUpper, ToLower, ToTitle and associated tests

R=rsc
DELTA=1578  (1007 added, 559 deleted, 12 changed)
OCL=33902
CL=33907

R=r
DELTA=1  (1 added, 0 deleted, 0 changed)
OCL=33887
CL=33904

R=rsc
DELTA=1  (1 added, 0 deleted, 0 changed)
OCL=33891
CL=33891

R=rsc
DELTA=113  (10 added, 30 deleted, 73 changed)
OCL=33877
CL=33882

R=r
DELTA=45  (45 added, 0 deleted, 0 changed)
OCL=33873
CL=33881

R=r
DELTA=60  (56 added, 3 deleted, 1 changed)
OCL=33868
CL=33872

R=rsc
DELTA=192  (192 added, 0 deleted, 0 changed)
OCL=33853
CL=33864

statement compiler will be fixed in a later CL.

The input and output of the expression compiler are now
clearly distinguished.  In the process, I made the individual
expression compilers operate on the compiled form of their
children instead of AST nodes.  As a result, there are now
fewer places where I hand-craft intermediate expression nodes.

The diff looks scarier than it is, mostly because exprCompiler
has been split into the input and output types, resulting in
lots of little renames.

R=rsc
APPROVED=rsc
DELTA=774  (204 added, 199 deleted, 371 changed)
OCL=33851
CL=33851

R=rsc
DELTA=444  (179 added, 177 deleted, 88 changed)
OCL=33847
CL=33849

R=r
DELTA=616  (598 added, 11 deleted, 7 changed)
OCL=33846
CL=33848

better FFI demo: compute fibonacci numbers using FFI'ed libgmp.

R=r
DELTA=281  (255 added, 19 deleted, 7 changed)
OCL=33815
CL=33820

Be more conservative: only mess with text/html and text/plain output.

R=rsc
APPROVED=rsc
DELTA=20  (12 added, 5 deleted, 3 changed)
OCL=33806
CL=33812

R=r
DELTA=494  (492 added, 0 deleted, 2 changed)
OCL=33784
CL=33810

move out of export data into its own section

R=r
DELTA=222  (71 added, 99 deleted, 52 changed)
OCL=33801
CL=33808

R=ken
OCL=33792
CL=33803

R=gri
DELTA=20  (17 added, 0 deleted, 3 changed)
OCL=33793
CL=33802

in a .6 file, an export line

	//ffi T localfib remotefib remote.so

means the dynamic linker should initialize
localfib, always a pointer, to the address of
remotefib, either text (T) or data (D) after
loading remote.so.

the C compiler will generate an export section
when given the pragmas

	#pragma package fib
	#pragma ffi T localfib remotefib remote.so

needing #pragma package is a bit of a kludge
and hopefully could go away later.

this is just the 6 tool chain support.
other architectures will happen once 6 settles down.

code using this to do FFI is in a later CL.

R=r
DELTA=161  (141 added, 14 deleted, 6 changed)
OCL=33783
CL=33795

R=rsc
DELTA=1  (0 added, 0 deleted, 1 changed)
OCL=33788
CL=33791

bug192.go:11:5: error: redefinition of ‘fmt’
bug192.go:9:8: note: previous definition of ‘fmt’ was here

R=r
DELTA=2  (0 added, 0 deleted, 2 changed)
OCL=33780
CL=33790

R=rsc
DELTA=9  (5 added, 0 deleted, 4 changed)
OCL=33768
CL=33785

R=ken
OCL=33778
CL=33781

R=rsc
APPROVED=rsc
DELTA=85  (35 added, 0 deleted, 50 changed)
OCL=33761
CL=33767

variables to be given initial values in some cases, to make
building global scopes more convenient.

R=rsc
APPROVED=rsc
DELTA=29  (17 added, 0 deleted, 12 changed)
OCL=33760
CL=33766

R=ken
OCL=33765
CL=33765

also fix echo bug that just surfaced in mkerrors.sh

R=r
DELTA=67  (11 added, 19 deleted, 37 changed)
OCL=33743
CL=33757

  * use //ffi comments in package import data
    to generate relocation entries and library loads.
  * call initffi in rt0.s if present

R=r
DELTA=117  (91 added, 3 deleted, 23 changed)
OCL=33739
CL=33750

R=ken
OCL=33745
CL=33745

R=ken
OCL=33730
CL=33730

  * more elf constants from FreeBSD
  * simple relocation demo

R=r
DELTA=410  (354 added, 49 deleted, 7 changed)
OCL=33689
CL=33729

R=rsc
DELTA=196  (118 added, 24 deleted, 54 changed)
OCL=33716
CL=33727

DELTA=11  (4 added, 0 deleted, 7 changed)
OCL=33698
CL=33712

6g's error for I4 is not quite accurate
(it calls I4 a non-interface) but also
not a crash or infinite loop.

R=iant
DELTA=15  (15 added, 0 deleted, 0 changed)
OCL=33701
CL=33709

R=rsc
APPROVED=rsc
DELTA=329  (301 added, 2 deleted, 26 changed)
OCL=33696
CL=33706

R=rsc
APPROVED=rsc
DELTA=23  (14 added, 8 deleted, 1 changed)
OCL=33699
CL=33705

PC/line/aline conversion methods.

R=rsc
APPROVED=rsc
DELTA=458  (434 added, 15 deleted, 9 changed)
OCL=33677
CL=33702

R=ken
OCL=33700
CL=33700

R=ken
OCL=33694
CL=33697