Correctly propagate toolchain setting in SConstruct.

test/cctest/SConscript

 # Copyright 2008 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 11 matching lines @@
 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 import sys
 from os.path import join, dirname, abspath
 root_dir = dirname(File('SConstruct').rfile().abspath)
 sys.path.append(join(root_dir, 'tools'))
-Import('context object_files')
+Import('context object_files tools')
 
 
 SOURCES = {
   'all': [
     'gay-fixed.cc',
     'gay-precision.cc',
     'gay-shortest.cc',
     'test-accessors.cc',
     'test-alloc.cc',
     'test-api.cc',
@@ skipping 57 matching lines @@
                 'test-disasm-mips.cc'],
   'os:linux':  ['test-platform-linux.cc'],
   'os:macos':  ['test-platform-macos.cc'],
   'os:nullos': ['test-platform-nullos.cc'],
   'os:win32':  ['test-platform-win32.cc']
 }
 
 
 def Build():
   cctest_files = context.GetRelevantSources(SOURCES)
-  env = Environment()
+  env = Environment(tools=tools)
   env.Replace(**context.flags['cctest'])
   context.ApplyEnvOverrides(env)
   # There seems to be a glitch in the way scons decides where to put
   # PDB files when compiling using MSVC so we specify it manually.
   # This should not affect any other platforms.
   return env.Program('cctest', ['cctest.cc', cctest_files, object_files],
       PDB='cctest.exe.pdb')
 
 
 program = Build()
 Return('program')