Fix #302: "python -m gevent.monkey" sets __file__

Thanks to frostedcheerios.

gevent/monkey.py

@@ -244,6 +244,7 @@ MONKEY OPTIONS: --verbose %s""" % ', '.join('--[no-]%s' % m for m in modules)
     if argv:
         sys.argv = argv
         __package__ = None
+        globals()['__file__'] = sys.argv[0]  # issue #302
         execfile(sys.argv[0])
     else:
         print (script_help)

greentest/test__issue302monkey.py

+import sys
+
+
+if 'gevent' not in sys.modules:
+    from subprocess import Popen, PIPE
+    args = [sys.executable, '-m', 'gevent.monkey', __file__]
+    p = Popen(args)
+    code = p.wait()
+    assert code == 0, code
+
+else:
+    import socket
+    assert 'gevent' in repr(socket.socket), repr(socket.socket)
+    assert __file__ == 'test__issue302monkey.py', repr(__file__)