osutil: switch to policy importer

"make clean" is recommended to test this change, though C API compatibility
should be preserved.

contrib/check-py3-compat.py

@@ -21,7 +21,6 b' import traceback'
     'bdiff.py',
     'diffhelpers.py',
     'mpatch.py',
-    'osutil.py',
     'parsers.py',
 )
 

contrib/import-checker.py

@@ -30,7 +30,6 b' allowsymbolimports = ('
     'bdiff.py',
     'diffhelpers.py',
     'mpatch.py',
-    'osutil.py',
     'parsers.py',
 )
 

contrib/wix/dist.wxs

@@ -16,7 +16,7 b''
           <File Name="mercurial.bdiff.pyd" />
           <File Name="mercurial.diffhelpers.pyd" />
           <File Name="mercurial.mpatch.pyd" />
-          <File Name="mercurial.osutil.pyd" />
+          <File Name="mercurial.cext.osutil.pyd" />
           <File Name="mercurial.parsers.pyd" />
           <File Name="pyexpat.pyd" />
           <File Name="bz2.pyd" />

mercurial/__init__.py

@@ -27,7 +27,6 b' modulepolicy = policy.policy'
     'mercurial.bdiff',
     'mercurial.diffhelpers',
     'mercurial.mpatch',
-    'mercurial.osutil',
     'mercurial.parsers',
 }
 

mercurial/debugcommands.py

@@ -1029,6 +1029,8 b' def debuginstall(ui, **opts):'
                 base85,
                 bdiff,
                 mpatch,
+            )
+            from .cext import (
                 osutil,
             )
             dir(bdiff), dir(mpatch), dir(base85), dir(osutil) # quiet pyflakes

mercurial/pure/osutil.py

@@ -13,7 +13,7 b' import os'
 import socket
 import stat as statmod
 
-from . import (
+from .. import (
     policy,
     pycompat,
 )

mercurial/util.py

@@ -46,11 +46,13 b' from . import ('
     encoding,
     error,
     i18n,
-    osutil,
     parsers,
+    policy,
     pycompat,
 )
 
+osutil = policy.importmod(r'osutil')
+
 b85decode = base85.b85decode
 b85encode = base85.b85encode
 

mercurial/windows.py

@@ -17,7 +17,7 b' import sys'
 from .i18n import _
 from . import (
     encoding,
-    osutil,
+    policy,
     pycompat,
     win32,
 )
@@ -28,6 +28,8 b' try:'
 except ImportError:
     import winreg
 
+osutil = policy.importmod(r'osutil')
+
 executablepath = win32.executablepath
 getuser = win32.getuser
 hidewindow = win32.hidewindow

setup.py

@@ -641,7 +641,7 b' extmodules = ['
                                     'mercurial/pathencode.c'],
               include_dirs=common_include_dirs,
               depends=common_depends),
-    Extension('mercurial.osutil', ['mercurial/osutil.c'],
+    Extension('mercurial.cext.osutil', ['mercurial/cext/osutil.c'],
               include_dirs=common_include_dirs,
               extra_compile_args=osutil_cflags,
               extra_link_args=osutil_ldflags,