diff --git a/Include/internal/pycore_fileutils.h b/Include/internal/pycore_fileutils.h
@@ -10,6 +10,12 @@ extern "C" {

#include <locale.h>   /* struct lconv */

PyAPI_DATA(int) _Py_HasFileSystemDefaultEncodeErrors;

PyAPI_FUNC(int) _Py_DecodeUTF8Ex(
@@ -33,6 +39,9 @@ PyAPI_FUNC(wchar_t*) _Py_DecodeUTF8_surrogateescape(
    Py_ssize_t arglen,
    size_t *wlen);

PyAPI_FUNC(int) _Py_GetForceASCII(void);

/* Reset "force ASCII" mode (if it was initialized).
@@ -65,6 +74,12 @@ extern int _Py_EncodeNonUnicodeWchar_InPlace(
    Py_ssize_t size);
#endif

#ifdef __cplusplus
}
#endif

@@ -82,6 +82,7 @@
#include "Python.h"
#include "pycore_initconfig.h"    // PyStatus
#include "pycore_pathconfig.h"    // _PyPathConfig
#include "osdefs.h"               // SEP, ALTSEP
#include <wchar.h>

@@ -115,10 +116,6 @@
 * with a semicolon separated path prior to calling Py_Initialize.
 */

-#ifndef LANDMARK
-#  define LANDMARK L"lib\\os.py"
-#endif
-
#define INIT_ERR_BUFFER_OVERFLOW() _PyStatus_ERR("buffer overflow")


@@ -216,7 +213,7 @@ exists(const wchar_t *filename)
   Assumes 'filename' MAXPATHLEN+1 bytes long -
   may extend 'filename' by one character. */
static int
-ismodule(wchar_t *filename, int update_filename)
{
    size_t n;

@@ -231,9 +228,8 @@ ismodule(wchar_t *filename, int update_filename)
        filename[n] = L'c';
        filename[n + 1] = L'\0';
        exist = exists(filename);
-        if (!update_filename) {
-            filename[n] = L'\0';
-        }
        return exist;
    }
    return 0;
@@ -253,7 +249,7 @@ ismodule(wchar_t *filename, int update_filename)
static void
join(wchar_t *buffer, const wchar_t *stuff)
{
-    if (FAILED(PathCchCombineEx(buffer, MAXPATHLEN+1, buffer, stuff, 0))) {
        Py_FatalError("buffer overflow in getpathp.c's join()");
    }
}
@@ -273,30 +269,37 @@ canonicalize(wchar_t *buffer, const wchar_t *path)
    return _PyStatus_OK();
}

-
-/* gotlandmark only called by search_for_prefix, which ensures
-   'prefix' is null terminated in bounds.  join() ensures
-   'landmark' can not overflow prefix if too long. */
static int
-gotlandmark(const wchar_t *prefix, const wchar_t *landmark)
{
-    wchar_t filename[MAXPATHLEN+1];
-    memset(filename, 0, sizeof(filename));
-    wcscpy_s(filename, Py_ARRAY_LENGTH(filename), prefix);
-    join(filename, landmark);
-    return ismodule(filename, FALSE);
}

-
/* assumes argv0_path is MAXPATHLEN+1 bytes long, already \0 term'd.
   assumption provided by only caller, calculate_path() */
static int
-search_for_prefix(wchar_t *prefix, const wchar_t *argv0_path, const wchar_t *landmark)
{
-    /* Search from argv0_path, until landmark is found */
-    wcscpy_s(prefix, MAXPATHLEN + 1, argv0_path);
    do {
-        if (gotlandmark(prefix, landmark)) {
            return 1;
        }
        reduce(prefix);
@@ -758,7 +761,7 @@ calculate_home_prefix(PyCalculatePath *calculate,
            reduce(prefix);
            calculate->home = prefix;
        }
-        else if (search_for_prefix(prefix, argv0_path, LANDMARK)) {
            calculate->home = prefix;
        }
        else {
@@ -936,7 +939,7 @@ calculate_module_search_path(PyCalculatePath *calculate,
            lookBuf[nchars] = L'\0';
            /* Up one level to the parent */
            reduce(lookBuf);
-            if (search_for_prefix(prefix, lookBuf, LANDMARK)) {
                break;
            }
            /* If we are out of paths to search - give up */