Problem building V8 on Windows 7

First I did:

git clean -dfx
svn co http://gyp.googlecode.com/svn/trunk build/gyp
svn co https://src.chromium.org/chrome/trunk/deps/third_party/icu46 third_party/icu
svn co http://src.chromium.org/svn/trunk/deps/third_party/cygwin@66844 third_party/cygwin
svn co http://src.chromium.org/svn/trunk/tools/third_party/python_26@89111 third_party/python_26

Then:

c:\compile\v8>set PATH=c:\compile\v8\third_party\python_26;%PATH%
c:\compile\v8>third_party\python_26\python.exe build\gyp_v8 -Dtarget_arch=x64
Updating projects from gyp files...
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "c:\compile\v8\third_party\python_26\lib\multiprocessing\forking.py", line 341, in main
    prepare(preparation_data)
  File "c:\compile\v8\third_party\python_26\lib\multiprocessing\forking.py", line 450, in prepare
    file, path_name, etc = imp.find_module(main_name, dirs)
ImportError: No module named gyp_v8
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "c:\compile\v8\third_party\python_26\lib\multiprocessing\forking.py", line 341, in main
    prepare(preparation_data)
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "c:\compile\v8\third_party\python_26\lib\multiprocessing\forking.py", line 450, in prepare
  File "c:\compile\v8\third_party\python_26\lib\multiprocessing\forking.py", line 341, in main
        file, path_name, etc = imp.find_module(main_name, dirs)
prepare(preparation_data)
ImportError  File "c:\compile\v8\third_party\python_26\lib\multiprocessing\forking.py", line 450, in prepare
: No module named gyp_v8
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "c:\compile\v8\third_party\python_26\lib\multiprocessing\forking.py", line 341, in main
    file, path_name, etc = imp.find_module(main_name, dirs)
ImportError: No module named gyp_v8
    prepare(preparation_data)
  File "c:\compile\v8\third_party\python_26\lib\multiprocessing\forking.py", line 450, in prepare
    file, path_name, etc = imp.find_module(main_name, dirs)
ImportError: No module named gyp_v8
Traceback (most recent call last):
  File "<string>", line 1, in <module>
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "c:\compile\v8\third_party\python_26\lib\multiprocessing\forking.py", line 341, in main
  File "c:\compile\v8\third_party\python_26\lib\multiprocessing\forking.py", line 341, in main
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "c:\compile\v8\third_party\python_26\lib\multiprocessing\forking.py", line 341, in main
        prepare(preparation_data)
prepare(preparation_data)
  File "c:\compile\v8\third_party\python_26\lib\multiprocessing\forking.py", line 450, in prepare
  File "c:\compile\v8\third_party\python_26\lib\multiprocessing\forking.py", line 450, in prepare
    prepare(preparation_data)
  File "c:\compile\v8\third_party\python_26\lib\multiprocessing\forking.py", line 450, in prepare
    file, path_name, etc = imp.find_module(main_name, dirs)
ImportError: N    o module named gyp_v8file, path_name, etc = imp.find_module(main_name, dirs)

ImportError    : file, path_name, etc = imp.find_module(main_name, dirs)
NImportErroro module named gyp_v8:
No module named gyp_v8
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "c:\compile\v8\third_party\python_26\lib\multiprocessing\forking.py", line 341, in main
    prepare(preparation_data)
  File "c:\compile\v8\third_party\python_26\lib\multiprocessing\forking.py", line 450, in prepare
    file, path_name, etc = imp.find_module(main_name, dirs)
ImportError: No module named gyp_v8