Modified PyImport_Import and PyImport_ImportModule to always use absolute imports by calling __import__ with an explicit level of 0

Added a new API function PyImport_ImportModuleNoBlock. It solves the problem with dead locks when mixing threads and imports

Modules/_cursesmodule.c

@@ -2255,7 +2255,7 @@ static int
 update_lines_cols(void)
 {
   PyObject *o;
-  PyObject *m = PyImport_ImportModule("curses");
+  PyObject *m = PyImport_ImportModuleNoBlock("curses");
 
   if (!m)
     return 0;