fix pyflakes warnings on PY3

gevent/hub.py

@@ -41,9 +41,10 @@ if PY3:
         raise value
 
 else:
-    string_types = basestring,
-    integer_types = (int, long)
-    xrange = xrange
+    import __builtin__
+    string_types = __builtin__.basestring,
+    integer_types = (int, __builtin__.long)
+    xrange = __builtin__.xrange
 
     from gevent._util_py2 import reraise
 

gevent/monkey.py

@@ -18,7 +18,8 @@ __all__ = ['patch_all',
 if sys.version_info[0] >= 3:
     string_types = str,
 else:
-    string_types = basestring,
+    import __builtin__
+    string_types = __builtin__.basestring
 
 
 # maps module name -> attribute name -> original item

greentest/six.py

@@ -34,5 +34,6 @@ else:
             locs = globs
         exec("""exec code in globs, locs""")
 
-    xrange = xrange
-    string_types = basestring,
+    import __builtin__ as builtins
+    xrange = builtins.xrange
+    string_types = builtins.basestring,