circular import when doing "import pandas" on pandas‑0.24.2‑cp38‑cp38m‑win_amd64.whl
Maybe it's the Python-3.8.0.a4 windows dll change ?

just a remark, as it's all alpha. using cgohlke first wheel on Python-3.8.0a4, I have a strange message

````
Python 3.8.0a4 (v3.8.0a4:c1004b8546, May  7 2019, 12:46:11) [MSC v.1916 32 bit (Intel)] on win32
Type "copyright", "credits" or "license()" for more information.
>>> import pandas
Traceback (most recent call last):
  File "<pyshell#0>", line 1, in <module>
    import pandas
  File "C:\WinP\bd38\bu\WPy32-3800a4\python-3.8.0a4\lib\site-packages\pandas\__init__.py", line 49, in <module>
    from pandas.io.api import *
  File "C:\WinP\bd38\bu\WPy32-3800a4\python-3.8.0a4\lib\site-packages\pandas\io\api.py", line 8, in <module>
    from pandas.io.excel import ExcelFile, ExcelWriter, read_excel
  File "C:\WinP\bd38\bu\WPy32-3800a4\python-3.8.0a4\lib\site-packages\pandas\io\excel.py", line 34, in <module>
    from pandas.io.parsers import TextParser
  File "C:\WinP\bd38\bu\WPy32-3800a4\python-3.8.0a4\lib\site-packages\pandas\io\parsers.py", line 19, in <module>
    import pandas._libs.parsers as parsers
  File "pandas\_libs\parsers.pyx", line 1418, in init pandas._libs.parsers
AttributeError: partially initialized module 'pandas' has no attribute '_NA_VALUES' (most likely due to a circular import)
>>> 
````
