[Python-3000] python -S

[Christian Heimes]

Brett Cannon wrote:
> Really? Without really digging into the code too much I see that if
> warnings were set on the command-line it's loaded, otherwise it's
> skipped.

You are right. It's not loaded by pythonrun.c. The io module is 
importing warnings w/o using it. I fixed it in r65694

./python -S -c "import sys; print(list(sorted(sys.modules)), 
len(sys.modules))"

Before:
['__main__', '_abcoll', '_codecs', '_fileio', '_sre', '_thread', 
'_warnings', '_weakref', '_weakrefset', 'abc', 'builtins', 'codecs', 
'copyreg', 'encodings', 'encodings.aliases', 'encodings.latin_1', 
'encodings.utf_8', 'errno', 'genericpath', 'io', 'linecache', 'os', 
'os.path', 'posix', 'posixpath', 're', 'signal', 'sre_compile', 
'sre_constants', 'sre_parse', 'stat', 'sys', 'types', 'warnings', 
'zipimport'] 35

After:
['__main__', '_abcoll', '_codecs', '_fileio', '_thread', '_weakref', 
'_weakrefset', 'abc', 'builtins', 'codecs', 'copyreg', 'encodings', 
'encodings.aliases', 'encodings.latin_1', 'encodings.utf_8', 'errno', 
'genericpath', 'io', 'os', 'os.path', 'posix', 'posixpath', 'signal', 
'stat', 'sys', 'zipimport'] 26

I'm able to remove copyreg as well. It's imported to register some 
pickle/unpickle hooks. The code can be moved into the copyreg module safely.

Christian