Fix Google App Engine ImportError.

Author: cocodrips

click/_compat.py

@@ -7,8 +7,9 @@
 
 
 PY2 = sys.version_info[0] == 2
-WIN = sys.platform.startswith('win')
 CYGWIN = sys.platform.startswith('cygwin')
+APP_ENGINE = os.environ.get('SERVER_SOFTWARE','').startswith('Development')
+WIN = sys.platform.startswith('win') and not APP_ENGINE
 DEFAULT_COLUMNS = 80