kconfig: sync to Linux 4.20

The previous sync was commit 18895514dc5e ("kconfig: update to
v3.18-rc6").

Some commits were applied on top of that since then, but equivalent
fixups were done in Linux.

So, this commit overwrites everything scripts/kconfig/ with the one
from Linux 4.20

Highlights:

 - 'silentoldconfig' has been renamed to 'syncconfig'
   (the top Makefile needs to be adjusted)

 - 'testconfig' target has been added for unit-tests
   (the top Makefile needs to export PYTHON3 because
    the test frame relies on Python3 and pytest)

 - The perfect hash table generated by gperf has been removed

 - The localization support has been removed

 - The 'option env=VAR' has been replaced with more generic
   variable reference syntax $(VAR)
   (./Kconfig and common/Kconfig need to be adjusted)

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 10 insertions, 0 deletions

diff --git a/scripts/kconfig/tests/err_recursive_inc/__init__.py b/scripts/kconfig/tests/err_recursive_inc/__init__.py
new file mode 100644
index 0000000000..0e4c839c54
--- /dev/null
+++ b/scripts/kconfig/tests/err_recursive_inc/__init__.py
@@ -0,0 +1,10 @@
+"""
+Detect recursive inclusion error.
+
+If recursive inclusion is detected, it should fail with error messages.
+"""
+
+
+def test(conf):
+    assert conf.oldaskconfig() != 0
+    assert conf.stderr_contains('expected_stderr')