Build in a ../sconsbuild directory by default:...

build/common.gypi

 # Copyright (c) 2009 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'variables': {
     # .gyp files should set chromium_code to 1 if they build Chromium-specific
     # code, as opposed to external code.  This variable is used to control
     # such things as the set of warnings to enable, and whether warnings are
     # treated as errors.
@@ skipping 117 matching lines @@
           '-mfpmath=sse',
         ],
         'linkflags': [
           '-m32',
           '-pthread',
         ],
         'scons_variable_settings': {
           'LIBPATH': ['$LIB_DIR'],
           # Linking of large files uses lots of RAM, so serialize links
           # using the handy flock command from util-linux.
-          'FLOCK_LINK': ['flock', '$DESTINATION_ROOT/linker.lock', '$LINK'],
+          'FLOCK_LINK': ['flock', '$TOP_BUILDDIR/linker.lock', '$LINK'],
 
           # We have several cases where archives depend on each other in
           # a cyclic fashion.  Since the GNU linker does only a single
           # pass over the archives we surround the libraries with
           # --start-group and --end-group (aka -( and -) ). That causes
           # ld to loop over the group until no more undefined symbols
           # are found. In an ideal world we would only make groups from
           # those libraries which we knew to be in cycles. However,
           # that's tough with SCons, so we bodge it by making all the
           # archives a group by redefining the linking command here.
@@ skipping 148 matching lines @@
       },
     }],
     ['chromium_code==0', {
       # This section must follow the other conditon sections above because
       # external_code.gypi expects to be merged into those settings.
       'includes': [
         'external_code.gypi',
       ],
     }],
   ],
+  'scons_settings': {
+    'sconsbuild_dir': '<(DEPTH)/sconsbuild',
+  },
   'xcode_settings': {
     # The Xcode generator will look for an xcode_settings section at the root
     # of each dict and use it to apply settings on a file-wide basis.  Most
     # settings should not be here, they should be in target-specific
     # xcode_settings sections, or better yet, should use non-Xcode-specific
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }