python3: update to 3.8.1

Drop backports, rebase other patches.

0001-main.c-if-OEPYTHON3HOME-is-set-use-instead-of-PYTHON.patch
is removed as the use case (allowing python 2 and 3 to coexist
in SDKs) is no longer relevant with Python 2.x reaching end of line
and upstream has refactored the code making a rebase difficult.
If needed, please re-add the patch to py2, rather than py3.

Python 3.8 no longer adds "m" to "3.8" in paths, so adjust the recipes
and classes accordingly.

The manifest for the 3.8.0 version is updated; particularly pkgutil
module is now packaged in -core (as other things in core need it);
this also necessitates allowing empty -pkgutil package to avoid
breakage across layers.

(From OE-Core rev: e6ab9f16b92aa1abdae82c535c1a452a1341b0e2)

Signed-off-by: Alexander Kanavin <alex.kanavin@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/python/python3/python-config.patch

@@ -1,4 +1,7 @@
-python-config: Revert to using distutils.sysconfig
+From 07df0ae0d70cba6d1847fe1c24a71063930bec60 Mon Sep 17 00:00:00 2001
+From: Tyler Hall <tylerwhall@gmail.com>
+Date: Sun, 4 May 2014 20:06:43 -0400
+Subject: [PATCH] python-config: Revert to using distutils.sysconfig
 
 The newer sysconfig module shares some code with distutils.sysconfig, but the same modifications as in
 
@@ -12,11 +15,16 @@ Upstream-Status: Inappropriate [Embedded Specific]
 
 Signed-off-by: Tyler Hall <tylerwhall@gmail.com>
 :
-Index: Python-3.3.3/Misc/python-config.in
-===================================================================
---- Python-3.3.3.orig/Misc/python-config.in
-+++ Python-3.3.3/Misc/python-config.in
-@@ -4,7 +4,7 @@
+
+---
+ Misc/python-config.in | 10 +++++-----
+ 1 file changed, 5 insertions(+), 5 deletions(-)
+
+diff --git a/Misc/python-config.in b/Misc/python-config.in
+index 727c4a8..c702829 100644
+--- a/Misc/python-config.in
++++ b/Misc/python-config.in
+@@ -6,7 +6,7 @@
  import getopt
  import os
  import sys
@@ -24,8 +32,8 @@ Index: Python-3.3.3/Misc/python-config.in
 +from distutils import sysconfig
  
  valid_opts = ['prefix', 'exec-prefix', 'includes', 'libs', 'cflags',
-               'ldflags', 'extension-suffix', 'help', 'abiflags', 'configdir']
-@@ -32,14 +32,14 @@ if '--help' in opt_flags:
+               'ldflags', 'extension-suffix', 'help', 'abiflags', 'configdir',
+@@ -35,14 +35,14 @@ if '--help' in opt_flags:
  
  for opt in opt_flags:
      if opt == '--prefix':