Index: Lib/distutils/tests/test_build_ext.py
===================================================================
--- Lib/distutils/tests/test_build_ext.py	(Revision 67313)
+++ Lib/distutils/tests/test_build_ext.py	(Arbeitskopie)
@@ -1,3 +1,4 @@
+import atexit
 import sys
 import os
 import tempfile
@@ -11,29 +12,43 @@
 import unittest
 from test import support
 
+# We have to use a single tempdir here. Otherwise every
+# iteration would keep references in Python/import.c:*extensions.
+TMP_DIR = None
+
+def cleanup_tmpdir():
+    if TMP_DIR is not None and os.path.isdir(TMP_DIR):
+        shutil.rmtree(TMP_DIR, os.name == 'nt' or sys.platform == 'cygwin')
+
+atexit.register(cleanup_tmpdir)
+
+
 class BuildExtTestCase(unittest.TestCase):
     def setUp(self):
+        global TMP_DIR
         # Create a simple test environment
         # Note that we're making changes to sys.path
-        self.tmp_dir = tempfile.mkdtemp(prefix="pythontest_")
+        if TMP_DIR is None:
+            TMP_DIR = tempfile.mkdtemp(prefix="pythontest_")
         self.sys_path = sys.path[:]
-        sys.path.append(self.tmp_dir)
+        sys.path.append(TMP_DIR)
 
         xx_c = os.path.join(sysconfig.project_base, 'Modules', 'xxmodule.c')
-        shutil.copy(xx_c, self.tmp_dir)
+        shutil.copy(xx_c, TMP_DIR)
 
     def test_build_ext(self):
-        xx_c = os.path.join(self.tmp_dir, 'xxmodule.c')
+        global ALREADY_TESTED
+        xx_c = os.path.join(TMP_DIR, 'xxmodule.c')
         xx_ext = Extension('xx', [xx_c])
         dist = Distribution({'name': 'xx', 'ext_modules': [xx_ext]})
-        dist.package_dir = self.tmp_dir
+        dist.package_dir = TMP_DIR
         cmd = build_ext(dist)
         if os.name == "nt":
             # On Windows, we must build a debug version iff running
             # a debug build of Python
             cmd.debug = sys.executable.endswith("_d.exe")
-        cmd.build_lib = self.tmp_dir
-        cmd.build_temp = self.tmp_dir
+        cmd.build_lib = TMP_DIR
+        cmd.build_temp = TMP_DIR
 
         old_stdout = sys.stdout
         if not support.verbose:
@@ -62,9 +77,14 @@
         # Get everything back to normal
         support.unload('xx')
         sys.path = self.sys_path
-        # XXX on Windows the test leaves a directory with xx module in TEMP
-        shutil.rmtree(self.tmp_dir, os.name == 'nt' or sys.platform == 'cygwin')
+        # clean the tmp dir but don't remove it
+        for path in (os.path.join(TMP_DIR, f) for f in os.listdir(TMP_DIR)):
+            if os.path.isdir(path):
+                shutil.rmtree(path, os.name == 'nt' or sys.platform == 'cygwin')
+            else:
+                os.unlink(path)
 
+
 def test_suite():
     if not sysconfig.python_build:
         if support.verbose: