Issue #13959: Rename imp to _imp and add Lib/imp.py and begin
rewriting functionality in pure Python.

To start, imp.new_module() has been rewritten in pure Python, put into
importlib (privately) and then publicly exposed in imp.
diff --git a/PC/os2emx/config.c b/PC/os2emx/config.c
index 218aa68..76c7ec6 100644
--- a/PC/os2emx/config.c
+++ b/PC/os2emx/config.c
@@ -150,7 +150,7 @@
     {"marshal", PyMarshal_Init},
 
     /* This lives it with import.c */
-    {"imp", initimp},
+    {"_imp", initimp},
 
     /* These entries are here for sys.builtin_module_names */
     {"__main__", NULL},