code review 6445082: pprof: make it work on windows again

pprof: make it work on windows again

- pprof is a perl script, so go command should invoke
  perl instead of trying to run pprof directly;
- pprof should use "go tool nm" unconditionally on windows,
  no one else can extract symbols from Go program;
- pprof should use "go tool nm" instead of "6nm".

Fixes issue 3879.

[brainman, 2012-08-07 02:31:20]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://go.googlecode.com/hg/

[r, 2012-08-17 18:26:24]

LGTM

[brainman, 2012-08-18 07:03:41]

*** Submitted as http://code.google.com/p/go/source/detail?r=7c5f4dad8fae ***

pprof: make it work on windows again

- pprof is a perl script, so go command should invoke
  perl instead of trying to run pprof directly;
- pprof should use "go tool nm" unconditionally on windows,
  no one else can extract symbols from Go program;
- pprof should use "go tool nm" instead of "6nm".

Fixes issue 3879.

R=golang-dev, r
CC=golang-dev
http://codereview.appspot.com/6445082