misc/cgo/stdio: make it work on Windows and also test it

use a function to get stdout and stderr, instead of depending
on a specific libc implementation.
also make test/run.go replace \r\n by \n before comparing
output.

        Fixes #2121.
        Part of issue 1741.

R=alex.brainman, rsc, r, remyoudompheng
CC=golang-dev
https://golang.org/cl/5847068

misc/cgo/stdio/stdio.go

+// skip
+
 // Copyright 2009 The Go Authors.  All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !netbsd
-
 package stdio
 
 /*
 #include <stdio.h>
+
+// on mingw, stderr and stdout are defined as &_iob[FILENO]
+// on netbsd, they are defined as &__sF[FILENO]
+// and cgo doesn't recognize them, so write a function to get them,
+// instead of depending on internals of libc implementation.
+FILE *getStdout(void) { return stdout; }
+FILE *getStderr(void) { return stderr; }
 */
 import "C"
 
-var Stdout = (*File)(C.stdout)
-var Stderr = (*File)(C.stderr)
+var Stdout = (*File)(C.getStdout())
+var Stderr = (*File)(C.getStderr())

misc/cgo/stdio/stdio_netbsd.go

-// Copyright 2009 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package stdio
-
-/*
-#include <stdio.h>
-
-extern FILE __sF[3];
-*/
-import "C"
-import "unsafe"
-
-var Stdout = (*File)(unsafe.Pointer(&C.__sF[1]))
-var Stderr = (*File)(unsafe.Pointer(&C.__sF[2]))

src/run.bat

@@ -70,11 +70,10 @@ if x%CGO_ENABLED% == x0 goto nocgo
 ::if errorlevel 1 goto fail
 ::echo.
 
-:: TODO ..\misc\cgo\stdio
-::echo # ..\misc\cgo\stdio
-::go run %GOROOT%\test\run.go - ..\misc\cgo\stdio
-::if errorlevel 1 goto fail
-::echo.
+echo # ..\misc\cgo\stdio
+go run %GOROOT%\test\run.go - ..\misc\cgo\stdio
+if errorlevel 1 goto fail
+echo.
 
 echo # ..\misc\cgo\test
 go test ..\misc\cgo\test

test/run.go

@@ -344,7 +344,7 @@ func (t *test) run() {
 		if err != nil {
 			t.err = fmt.Errorf("%s\n%s", err, out)
 		}
-		if string(out) != t.expectedOutput() {
+		if strings.Replace(string(out), "\r\n", "\n", -1) != t.expectedOutput() {
 			t.err = fmt.Errorf("incorrect output\n%s", out)
 		}