build: scripts/config - update to kconfig-v5.6

Major changes include:
 - Much more readable reverse dependencies separated in groups
 - Improved recursive dependency report
 - More readable .config files: add comments to signal end of menus
 - More warnings for incorrect Config.in entries, such as a 'choice'
   default not contained in the 'choice'
 - Hability to properly display pseudographics with non-latin locales
 - Recursive dependencies can optionally be treated as errors

Changes from failed dcf3e63a35d05e7e5103819c0f17195bfafe9baa attempt:
 - Recursive dependencies are treated as warnings by default
 - The option to treat them as errors is implemented as a command-line
   flag to scripts/config/conf instead of a compile-time definition
 - fixed handling of select with umnet dependencies

Cc: Petr Štetiar <ynezz@true.cz>
Cc: Jo-Philip Wich <jow@mein.io>
Signed-off-by: Eneas U de Queiroz <cotequeiroz@gmail.com>

1 files changed, 27 insertions, 2 deletions

diff --git a/scripts/config/README b/scripts/config/README
index ea911be6a7..1e94ee46f1 100644
--- a/scripts/config/README
+++ b/scripts/config/README
@@ -1,2 +1,27 @@
-These files were taken from the Linux 3.9 Kernel
-Configuration System and modified for the OpenWrt Buildroot.
+These files were taken from the Linux Kernel Configuration System at commit
+089b7d890f972f6b649fedc9259f6b93a18fb970 (Feb 4, 2020) and modified for the
+OpenWrt Buildroot:
+ - Removed nconf, gconf, tests and kernel configuration targets.
+ - Adjusted the Makefile to compile outside the kernel.
+ - Always use default file when running make all{no,mod,yes}config.
+ - Added a 'reset' command to reset config when the target changes.
+ - Allow config reading from & writing to a different file.
+ - Allow 'source' command to use globs to include multiple files.
+ - Don't warn when selecting a symbol with unmet direct dependencies.
+ - Don't write auto.conf and other files under include/ directory.
+ - Reverted a commit to allow use of '/' & '.' in unquoted config symbols.
+   There are too many of those in OpenWrt right now.
+ - Reverted a commit that was issuing a warning when there were more than
+   one help text.  This is used in a few packages to use different texts
+   for the menuconfig help, and the ipkg package description.
+ - Reverted an upstream change that avoids writing symbols that are not
+   visible to .config, which breaks OpenWrt busybox's '.config' generation
+   logic.
+ - Treat recursive dependency as a warning only; add a --fatalrecursive
+   option to conf to treat recursive deps as a fatal error.
+ - Use pre-built *.lex.c *.tab.[ch] files by default, to avoid depending on
+   flex & bison.  Rebuild/remove these files only if running make with
+   BUILD_SHIPPED_FILES defined
+
+For a full list of changes, see the repository at:
+https://github.com/cotequeiroz/linux/commits/openwrt/scripts/kconfig