Index: Python-3.4.2/Lib/ensurepip/__init__.py
===================================================================
--- Python-3.4.2.orig/Lib/ensurepip/__init__.py
+++ Python-3.4.2/Lib/ensurepip/__init__.py
@@ -3,6 +3,7 @@ import os.path
 import pkgutil
 import sys
 import tempfile
+import pwd
 
 
 __all__ = ["version", "bootstrap"]
@@ -36,6 +37,15 @@ def _run_pip(args, additional_paths=None
     if additional_paths is not None:
         sys.path = additional_paths + sys.path
 
+    # Explicitly make sure pip build directory was left clean
+    user = pwd.getpwuid(os.getuid())[0]
+    if os.path.exists("/tmp/pip_build_" + user + "/pip-delete-this-directory.txt"):
+        os.remove("/tmp/pip_build_" + user + "/pip-delete-this-directory.txt")
+        try:
+            os.rmdir("/tmp/pip_build_" + user + "/")
+        except OSError:
+            print("Error: Pip build directory (%s) was left unclean, make sure it is clean before continuing\n" % ("/tmp/pip_build_" + user + "/"))
+
     # Install the bundled software
     import pip
     pip.main(args)