diff -Naur Python-3.5.2-orig/configure.ac Python-3.5.2/configure.ac
--- Python-3.5.2-orig/configure.ac	2016-07-12 14:21:55.830300700 +0300
+++ Python-3.5.2/configure.ac	2016-07-12 14:22:00.308800700 +0300
@@ -5373,7 +5373,7 @@
 case $host in
   *-*-mingw*)
     dnl default sys.path calculations for windows platforms
-    MODULE_GETPATH=PC/getpathp.o
+    MODULE_GETPATH=Modules/getpath.o
     ;;
 esac
 
diff -Naur Python-3.5.2-orig/Modules/getpath.c Python-3.5.2/Modules/getpath.c
--- Python-3.5.2-orig/Modules/getpath.c	2016-07-12 14:21:59.929800700 +0300
+++ Python-3.5.2/Modules/getpath.c	2016-07-12 14:22:00.325800700 +0300
@@ -10,6 +10,10 @@
 #include <mach-o/dyld.h>
 #endif
 
+#ifdef MS_WINDOWS
+#include <windows.h>
+#endif
+
 /* Search in some common locations for the associated Python libraries.
  *
  * Two directories must be found, the platform independent directory
@@ -109,9 +113,17 @@
 #define LANDMARK L"os.py"
 #endif
 
+#ifdef __MINGW32__
+#define wcstok(line, delim, pointer)  wcstok(line, delim)
+#endif
+
 static wchar_t prefix[MAXPATHLEN+1];
 static wchar_t exec_prefix[MAXPATHLEN+1];
 static wchar_t progpath[MAXPATHLEN+1];
+#ifdef MS_WINDOWS
+static wchar_t dllpath[MAXPATHLEN+1];
+extern HANDLE PyWin_DLLhModule;
+#endif
 static wchar_t *module_search_path = NULL;
 
 /* Get file status. Encode the path to the locale encoding. */
@@ -137,7 +149,7 @@
     size_t i = wcslen(dir);
     while (i > 0 && dir[i] != Py_GetSepW(dir))
         --i;
-    dir[i] = '\0';
+    dir[i] = 0;
 }
 
 static int
@@ -455,6 +467,26 @@
     return 0;
 }
 
+#ifdef MS_WINDOWS
+/* Calculates dllpath and progpath, replacing \\ with / */
+int GetWindowsModulePaths()
+{
+    int result = 0;
+    result = GetModuleFileNameW(NULL, progpath, MAXPATHLEN);
+    Py_NormalizeSepsW(progpath);
+    dllpath[0] = 0;
+#ifdef Py_ENABLE_SHARED
+    if (PyWin_DLLhModule) {
+        if((GetModuleFileNameW(PyWin_DLLhModule, dllpath, MAXPATHLEN) > 0)) {
+            result = 1;
+            Py_NormalizeSepsW(dllpath);
+        }
+    }
+#endif
+    return result;
+}
+#endif /* MS_WINDOWS */
+
 static void
 calculate_path(void)
 {
@@ -534,6 +566,10 @@
         }
     }
 #endif /* __APPLE__ */
+#ifdef MS_WINDOWS
+    else if(GetWindowsModulePaths()) {
+    }
+#endif /* MS_WINDOWS */
     else if (path) {
         while (1) {
             wchar_t *delim = wcschr(path, DELIM);
@@ -872,6 +908,45 @@
 }
 
 
+#ifdef MS_WINDOWS
+/* Load python3.dll before loading any extension module that might refer
+   to it. That way, we can be sure that always the python3.dll corresponding
+   to this python DLL is loaded, not a python3.dll that might be on the path
+   by chance.
+   Return whether the DLL was found.
+*/
+static int python3_checked = 0;
+static HANDLE hPython3;
+int
+_Py_CheckPython3()
+{
+    wchar_t py3path[MAXPATHLEN+1];
+    wchar_t *s;
+    if (python3_checked)
+        return hPython3 != NULL;
+    python3_checked = 1;
+
+    /* If there is a python3.dll next to the python3y.dll,
+       assume this is a build tree; use that DLL */
+    wcscpy(py3path, dllpath);
+    s = wcsrchr(py3path, Py_GetSepW(py3path));
+    if (!s)
+        s = py3path;
+    else
+        s += 1;
+    wcscpy(s, L"python3.dll");
+    hPython3 = LoadLibraryExW(py3path, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
+    if (hPython3 != NULL)
+        return 1;
+
+    /* Check sys.prefix\DLLs\python3.dll */
+    wcscpy(py3path, Py_GetPrefix());
+    wcscat(py3path, L"\\DLLs\\python3.dll");
+    hPython3 = LoadLibraryExW(py3path, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
+    return hPython3 != NULL;
+}
+#endif
+
 #ifdef __cplusplus
 }
 #endif
diff -Naur Python-3.5.2-orig/Modules/posixmodule.c Python-3.5.2/Modules/posixmodule.c
--- Python-3.5.2-orig/Modules/posixmodule.c	2016-07-12 14:21:59.946800700 +0300
+++ Python-3.5.2/Modules/posixmodule.c	2016-07-12 14:22:00.338300700 +0300
@@ -3550,7 +3550,7 @@
             Py_END_ALLOW_THREADS
             /* FindNextFile sets error to ERROR_NO_MORE_FILES if
                it got to the end of the directory. */
-            if (!result && GetLastError() != ERROR_NO_MORE_FILES) {
+            if (!result && GetLastError() != 0 && GetLastError() != ERROR_NO_MORE_FILES) {
                 Py_DECREF(list);
                 list = path_error(path);
                 goto exit;
@@ -3605,7 +3605,7 @@
         Py_END_ALLOW_THREADS
         /* FindNextFile sets error to ERROR_NO_MORE_FILES if
            it got to the end of the directory. */
-        if (!result && GetLastError() != ERROR_NO_MORE_FILES) {
+        if (!result && GetLastError() != 0 && GetLastError() != ERROR_NO_MORE_FILES) {
             Py_DECREF(list);
             list = path_error(path);
             goto exit;