python3targetconfig.bbclass: use PYTHONPATH to point to the target config

There is no need to patch native python so that it looks in the target
sysroot; the same can be achieved with just an environment variable.

(From OE-Core rev: c9617c03bceee54dc540318cada392799b137bd5)

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/python/python3/0001-distutils-sysconfig-append-STAGING_LIBDIR-python-sys.patch

@@ -1,28 +0,0 @@
-From 9c6b9f46179c8f9c9391767e2b02f268a1ee7a9c Mon Sep 17 00:00:00 2001
-From: Alexander Kanavin <alex.kanavin@gmail.com>
-Date: Thu, 31 Jan 2019 16:46:30 +0100
-Subject: [PATCH] distutils/sysconfig: append
- STAGING_LIBDIR/python-sysconfigdata to sys.path
-
-So that target configuration can be used when running native python
-
-Upstream-Status: Inappropriate [oe-core specific]
-Signed-off-by: Alexander Kanavin <alex.kanavin@gmail.com>
-
----
- Lib/sysconfig.py | 2 ++
- 1 file changed, 2 insertions(+)
-
-diff --git a/Lib/sysconfig.py b/Lib/sysconfig.py
-index ff399e2..95844cf 100644
---- a/Lib/sysconfig.py
-+++ b/Lib/sysconfig.py
-@@ -528,6 +528,8 @@ def _init_posix(vars):
-     """Initialize the module as appropriate for POSIX systems."""
-     # _sysconfigdata is generated at build time, see _generate_posix_vars()
-     name = _get_sysconfigdata_name()
-+    if 'STAGING_LIBDIR' in os.environ:
-+        sys.path.append(os.environ['STAGING_LIBDIR']+'/python-sysconfigdata')
-     _temp = __import__(name, globals(), locals(), ['build_time_vars'], 0)
-     build_time_vars = _temp.build_time_vars
-     vars.update(build_time_vars)