MinGW support: Add patches-win32/01-dynload_win.patch

This commit integrates changes originally added to the project
as python-cmake-buildsystem/python-cmake-buildsystem@18d49757e (Mingw32 support, and add cmake
options for disabling)

Note that in  more recent version of Python, this patch is obsoleted
by the following commits:

  See python/cpython@589f89e2a (introduced in 3.3)
      Removed a Windows 9x trick used before LoadLibraryExW.
      Windows 9x has long been unsupported and the result of GetFullPathName was not even
      being used in the first place.

  See python/cpython@05f2d84ca (introduced in 3.9)
      bpo-28269: Replace strcasecmp with system function _stricmp. (pythonGH-13095)

Co-authored-by: David Sansome <[email protected]>

Author: jcfr

Python/dynload_win.c

@@ -25,24 +25,6 @@ const struct filedescr _PyImport_DynLoadFiletab[] = {
 };
 
 
-/* Case insensitive string compare, to avoid any dependencies on particular
-   C RTL implementations */
-
-static int strcasecmp (char *string1, char *string2)
-{
-    int first, second;
-
-    do {
-        first  = tolower(*string1);
-        second = tolower(*string2);
-        string1++;
-        string2++;
-    } while (first && first == second);
-
-    return (first - second);
-}
-
-
 /* Function to return the name of the "python" DLL that the supplied module
    directly imports.  Looks through the list of imported modules and
    returns the first entry that starts with "python" (case sensitive) and
@@ -186,6 +168,7 @@ dl_funcptr _PyImport_GetDynLoadFunc(const char *fqname, const char *shortname,
         /* Don't display a message box when Python can't load a DLL */
         old_mode = SetErrorMode(SEM_FAILCRITICALERRORS);
 
+#ifdef Py_ENABLE_SHARED
         if (GetFullPathName(pathname,
                             sizeof(pathbuf),
                             pathbuf,
@@ -196,6 +179,7 @@ dl_funcptr _PyImport_GetDynLoadFunc(const char *fqname, const char *shortname,
                                  LOAD_WITH_ALTERED_SEARCH_PATH);
             _Py_DeactivateActCtx(cookie);
         }
+#endif // Py_ENABLE_SHARED
 
         /* restore old error mode settings */
         SetErrorMode(old_mode);