This avoids a crash when using cgo where glibc's malloc thinks
that it can use some of the memory following the symbol table.
This fails because the symbol table is mapped read-only, which
affects the whole page.

R=rsc
CC=golang-dev
https://golang.org/cl/1616042

R=rsc
CC=golang-dev
https://golang.org/cl/1381041

R=rsc
CC=golang-dev
https://golang.org/cl/1652041

R=r
CC=golang-dev
https://golang.org/cl/1615042

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/1555042

R=rsc
CC=golang-dev
https://golang.org/cl/1585041

R=r
CC=golang-dev
https://golang.org/cl/1649041

R=rsc
CC=golang-dev
https://golang.org/cl/1633042

Although technically incorrect, we want this in order to parse X.509
certificates where a wildcard hostname ("*.example.com") has been put
into a PrintableString.

Fixes #850.

R=rsc
CC=golang-dev
https://golang.org/cl/1615043

R=r
CC=golang-dev
https://golang.org/cl/1644042

R=r
CC=golang-dev
https://golang.org/cl/1599043

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/1636043

R=rsc
CC=golang-dev
https://golang.org/cl/1626043

R=rsc
CC=golang-dev
https://golang.org/cl/1644041

 * disallow surrogate pair runes.
 * diagnose impossible type assertions
 * eliminate another static buffer.
 * do not overflow lexbuf.
 * add -u flag to disable package unsafe.

R=ken2
CC=golang-dev
https://golang.org/cl/1619042

R=r
CC=golang-dev
https://golang.org/cl/1631041

* Code for assignment, conversions now mirrors spec.
* Changed some snprint -> smprint.
* Renamed runtime functions to separate
  interface conversions from type assertions:
  convT2I, assertI2T, etc.
* Correct checking of \U sequences.

Fixes #840.
Fixes #830.
Fixes #778.

R=ken2
CC=golang-dev
https://golang.org/cl/1303042

R=gri
CC=golang-dev
https://golang.org/cl/1620042

(remains of the semicolon conversion)

R=rsc
CC=golang-dev
https://golang.org/cl/1623041

R=rsc
CC=golang-dev
https://golang.org/cl/1621041

(caused certain files to not be idempotent under gofmt)

- corrected golden files for go/printer
- slightly simplified some code in nodes.go (no impact on formatting)
- these changes have no impact on gofmt output of .go files under src, misc

fallthrough statement considered harmful!

R=rsc
CC=golang-dev
https://golang.org/cl/1593042

R=gri
CC=golang-dev
https://golang.org/cl/1616041

R=r
CC=golang-dev
https://golang.org/cl/1614041

R=gri
CC=golang-dev
https://golang.org/cl/1612041

*T2 implements I2, but T2 does not.

R=gri
CC=golang-dev
https://golang.org/cl/1613041

Fixes #844.

R=ken2, rsc, ken3
CC=golang-dev
https://golang.org/cl/1593041

Fixes #827.

R=ken2
CC=golang-dev, rsc
https://golang.org/cl/1592041

R=r, rsc
CC=golang-dev
https://golang.org/cl/1590041

R=rsc
CC=golang-dev
https://golang.org/cl/1581041

Specifically:
- introduced notion of "underlying type"
- removed notion of type compatibility
- consolidated rules about assignment compatibility in
  assignment compatibility section
- be consistent with specyfing that nil is the value
  for uninitialized variables that can be nil (this
  was not specified clearly for pointers, functions, interfaces)
- added/fixed various related links throughout
- clarify language on conversions

R=rsc, r, iant, ken2
CC=golang-dev
https://golang.org/cl/1536041

R=rsc
CC=golang-dev
https://golang.org/cl/1514041

R=r
CC=golang-dev
https://golang.org/cl/1535041

R=r
CC=golang-dev
https://golang.org/cl/1539042

R=rsc, iant
CC=golang-dev
https://golang.org/cl/1567041

R=rsc
CC=golang-dev
https://golang.org/cl/1559041

R=gri
CC=golang-dev
https://golang.org/cl/1548042

Time (us) to draw a 200x200 src onto an image.RGBA dst with the Over
operator. Each case was measured three separate times, and the sorted
times are reported.

Fill case (where src is an image.ColorImage):
Before:
7438, 7511, 7526
After:
3073, 3087, 3102

Copy case (where src is an image.RGBA):
Before:
9506, 9510, 9563
After:
5262, 5300, 5344

R=rsc
CC=golang-dev
https://golang.org/cl/1532041

R=rsc
CC=golang-dev
https://golang.org/cl/1533041

R=rsc
CC=golang-dev
https://golang.org/cl/1518042

Specifically:
- Simplified definition of comparison compatibility and folded into
  section on comparison operators since it's only used there.

This is a small language change/cleanup. As a consequence:
- An interface value may now be compared against a non-interface value.
- Channels with opposite directions cannot be compared directly anymore
  (per discussion with rsc).

R=rsc, r, iant, ken2
CC=golang-dev
https://golang.org/cl/1462041