diff -r e9497423de7a Include/pythonrun.h
--- a/Include/pythonrun.h	Tue Sep 06 14:08:24 2011 +0100
+++ b/Include/pythonrun.h	Tue Sep 06 16:51:39 2011 +0200
@@ -167,6 +167,7 @@
 PyAPI_FUNC(wchar_t *) Py_GetPrefix(void);
 PyAPI_FUNC(wchar_t *) Py_GetExecPrefix(void);
 PyAPI_FUNC(wchar_t *) Py_GetPath(void);
+PyAPI_FUNC(void)      Py_ImportLandmark(void);
 PyAPI_FUNC(void)      Py_SetPath(const wchar_t *);
 #ifdef MS_WINDOWS
 int _Py_CheckPython3();
diff -r e9497423de7a Modules/getpath.c
--- a/Modules/getpath.c	Tue Sep 06 14:08:24 2011 +0100
+++ b/Modules/getpath.c	Tue Sep 06 16:51:39 2011 +0200
@@ -51,7 +51,7 @@
  * pybuilddir.txt.  If the landmark is found, we're done.
  *
  * For the remaining steps, the prefix landmark will always be
- * lib/python$VERSION/os.py and the exec_prefix will always be
+ * lib/python$VERSION/stdlib_landmark.py and the exec_prefix will always be
  * lib/python$VERSION/lib-dynload, where $VERSION is Python's version
  * number as supplied by the Makefile.  Note that this means that no more
  * build directory checking is performed; if the first step did not find
@@ -127,7 +127,12 @@
 #endif
 
 #ifndef LANDMARK
-#define LANDMARK L"os.py"
+#define LANDMARK L"stdlib_landmark.py"
+#define LANDMARK_MODULE "stdlib_landmark"
+#else
+#ifndef LANDMARK_MODULE
+#error LANDMARK defined but not LANDMARK_MODULE
+#endif
 #endif
 
 static wchar_t prefix[MAXPATHLEN+1];
@@ -778,6 +783,31 @@
     return progpath;
 }
 
+void
+Py_ImportLandmark(void)
+{
+    PyObject *m = PyImport_ImportModule(LANDMARK_MODULE);
+    if (m == NULL) {
+        PyObject *f = PySys_GetObject("stderr");
+        if (Py_VerboseFlag) {
+            PyFile_WriteString(
+                "'import " LANDMARK_MODULE "' failed; traceback:\n", f);
+            PyErr_Print();
+        }
+        else {
+            /* Ignore a missing landmark module; if the stdlib wasn't
+             * properly located the next import (of 'site') will have
+             * instructions to run Python with '-v', which will show the
+             * above traceback.  If it *was* properly located, the landmark
+             * module probably isn't important anymore.
+             */
+            PyErr_Clear();
+        }
+    }
+    else {
+        Py_DECREF(m);
+    }
+}
 
 #ifdef __cplusplus
 }
diff -r e9497423de7a Python/pythonrun.c
--- a/Python/pythonrun.c	Tue Sep 06 14:08:24 2011 +0100
+++ b/Python/pythonrun.c	Tue Sep 06 16:51:39 2011 +0200
@@ -314,6 +314,9 @@
     if (install_sigs)
         initsigs(); /* Signal handling stuff, including initintr() */
 
+    /* Make sure the stdlib is available by importing the landmark. */
+    Py_ImportLandmark();
+
     initmain(); /* Module __main__ */
     if (initstdio() < 0)
         Py_FatalError(
@@ -640,6 +643,7 @@
         if (initstdio() < 0)
             Py_FatalError(
             "Py_Initialize: can't initialize sys standard streams");
+        Py_ImportLandmark();
         initmain();
         if (!Py_NoSiteFlag)
             initsite();