[PATCHv2] kconfig: add some Kconfig env variables to make help

[Sergey Senozhatsky]

Add a new section "Configuration environment variables" to
`make help` output in order to make it easier for people to
discover KCONFIG_WERROR, etc.

Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
---
 scripts/kconfig/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
index ea1bf3b3dbde..0044d49e149c 100644
--- a/scripts/kconfig/Makefile
+++ b/scripts/kconfig/Makefile
@@ -158,6 +158,10 @@ help:
 		if help=$$(grep -m1 '^# Help: ' $(f)); then \
 			printf '  %-25s - %s\n' '$(notdir $(f))' "$${help#*: }"; \
 		fi;)
+	@echo  ''
+	@echo  'Configuration environment variables:'
+	@echo  '  KCONFIG_WERROR                 - Turn some Kconfig warnings into error conditions'
+	@echo  '  KCONFIG_WARN_UNKNOWN_SYMBOLS   - Make Kconfig warn about all unrecognized config symbols'
 
 # ===========================================================================
 # object files used by all kconfig flavours
-- 
2.44.0.rc0.258.g7320e95886-goog