MSVS output to /build/ dir.

tools/gyp/msvs.gypi

+# Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+# for details. All rights reserved. Use of this source code is governed by a
+# BSD-style license that can be found in the LICENSE file.
+
+{
+  'target_defaults': {
+    'msvs_configuration_attributes': {
+      # DON'T ADD ANYTHING NEW TO THIS BLOCK UNLESS YOU REALLY REALLY NEED IT!
+      # This block adds *project-wide* configuration settings to each project
+      # file.  It's almost always wrong to put things here. Instead, specify
+      # your custom msvs_configuration_attributes in a target_defaults section
+      # of a .gypi file that is explicitly included.
+      'OutputDirectory': '<(DEPTH)\\build\\$(ConfigurationName)',
+      'IntermediateDirectory': '$(OutDir)\\obj\\$(ProjectName)',
+    },
+  }
+}