Get binstubs working on Windows.

sdk/bin/pub.bat

 @echo off
 REM Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 REM for details. All rights reserved. Use of this source code is governed by a
 REM BSD-style license that can be found in the LICENSE file.
 
 rem Run pub.dart on the Dart VM. This script is only used when running pub from
 rem within the Dart source repo. The shipped SDK instead uses "pub_sdk.bat",
 rem which is renamed to "pub.bat" when the SDK is built.
 
 setlocal
@@ skipping 22 matching lines @@
 set BUILD_DIR=%SDK_DIR%\..\build\ReleaseIA32
 set PACKAGES_DIR=%BUILD_DIR%\pub_packages
 set DART=%BUILD_DIR%\dart-sdk\bin\dart
 
 rem Compile async/await down to vanilla Dart.
 rem TODO(rnystrom): Remove this when #104 is fixed.
 set ASYNC_COMPILER="%SDK_DIR%"\lib\_internal\pub\bin\async_compile.dart
 "%DART%" --package-root="%PACKAGES_DIR%" "%ASYNC_COMPILER%" "%BUILD_DIR%"
 
 rem Run the async/await compiled pub.
-set PUB="%SDK_DIR%"\lib\_internal\pub_generated\bin\pub.dart"
+set PUB="%SDK_DIR%\lib\_internal\pub_generated\bin\pub.dart"
 "%DART%" %VM_OPTIONS% --package-root="%PACKAGES_DIR%" "%PUB%" %*
 
 endlocal
 
 exit /b %errorlevel%
 
 :follow_links
 setlocal
 for %%i in (%1) do set result=%%~fi
 set current=
 for /f "usebackq tokens=2 delims=[]" %%i in (`dir /a:l "%~dp1" 2^>nul ^
                                              ^| find ">     %~n1 ["`) do (
   set current=%%i
 )
 if not "%current%"=="" call :follow_links "%current%", result
 endlocal & set %~2=%result%
 goto :eof
 
-:end
+:end