fixed the export symbols for the win32 linker
diff --git a/Lib/packaging/command/build_ext.py b/Lib/packaging/command/build_ext.py
index 9b71041..7803d01 100644
--- a/Lib/packaging/command/build_ext.py
+++ b/Lib/packaging/command/build_ext.py
@@ -589,7 +589,7 @@
         provided, "init" + module_name.  Only relevant on Windows, where
         the .pyd file (DLL) must export the module "init" function.
         """
-        initfunc_name = "init" + ext.name.split('.')[-1]
+        initfunc_name = "PyInit_" + ext.name.split('.')[-1]
         if initfunc_name not in ext.export_symbols:
             ext.export_symbols.append(initfunc_name)
         return ext.export_symbols
diff --git a/Lib/packaging/tests/test_command_build_ext.py b/Lib/packaging/tests/test_command_build_ext.py
index 2d79842..9dfa26b 100644
--- a/Lib/packaging/tests/test_command_build_ext.py
+++ b/Lib/packaging/tests/test_command_build_ext.py
@@ -239,7 +239,7 @@
     def test_get_outputs(self):
         tmp_dir = self.mkdtemp()
         c_file = os.path.join(tmp_dir, 'foo.c')
-        self.write_file(c_file, 'void initfoo(void) {};\n')
+        self.write_file(c_file, 'void PyInit_foo(void) {};\n')
         ext = Extension('foo', [c_file], optional=False)
         dist = Distribution({'name': 'xx',
                              'ext_modules': [ext]})