scripts: merge_config: Add option to suppress warning on overrides

Currently merge_config.sh will unconditionally warn if a fragment overrides
any already set symbol. This is generally desirable but is inconvenient in
cases where we want to create a fragment which disables unwanted options in
the base configuration, for example when attempting to produce a smaller
version of another configuration.

Add an option -Q which will suppress these warnings.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230203-arm64-defconfigs-v1-1-cd0694a05f13@kernel.orgSigned-off-by: Arnd Bergmann <arnd@arndb.de>

scripts/kconfig/merge_config.sh

@@ -29,6 +29,7 @@ usage() {
 	echo "  -y    make builtin have precedence over modules"
 	echo "  -O    dir to put generated output files.  Consider setting \$KCONFIG_CONFIG instead."
 	echo "  -s    strict mode. Fail if the fragment redefines any value."
+	echo "  -Q    disable warning messages for overridden options."
 	echo
 	echo "Used prefix: '$CONFIG_PREFIX'. You can redefine it with \$CONFIG_ environment variable."
 }
@@ -40,6 +41,7 @@ BUILTIN=false
 OUTPUT=.
 STRICT=false
 CONFIG_PREFIX=${CONFIG_-CONFIG_}
+WARNOVERRIDE=echo
 
 while true; do
 	case $1 in
@@ -82,6 +84,11 @@ while true; do
 		shift
 		continue
 		;;
+	"-Q")
+		WARNOVERRIDE=true
+		shift
+		continue
+		;;
 	*)
 		break
 		;;
@@ -138,21 +145,21 @@ for ORIG_MERGE_FILE in $MERGE_LIST ; do
 		NEW_VAL=$(grep -w $CFG $MERGE_FILE)
 		BUILTIN_FLAG=false
 		if [ "$BUILTIN" = "true" ] && [ "${NEW_VAL#CONFIG_*=}" = "m" ] && [ "${PREV_VAL#CONFIG_*=}" = "y" ]; then
-			echo Previous  value: $PREV_VAL
-			echo New value:       $NEW_VAL
-			echo -y passed, will not demote y to m
-			echo
+			${WARNOVVERIDE} Previous  value: $PREV_VAL
+			${WARNOVERRIDE} New value:       $NEW_VAL
+			${WARNOVERRIDE} -y passed, will not demote y to m
+			${WARNOVERRIDE}
 			BUILTIN_FLAG=true
 		elif [ "x$PREV_VAL" != "x$NEW_VAL" ] ; then
-			echo Value of $CFG is redefined by fragment $ORIG_MERGE_FILE:
-			echo Previous  value: $PREV_VAL
-			echo New value:       $NEW_VAL
-			echo
+			${WARNOVERRIDE} Value of $CFG is redefined by fragment $ORIG_MERGE_FILE:
+			${WARNOVERRIDE} Previous  value: $PREV_VAL
+			${WARNOVERRIDE} New value:       $NEW_VAL
+			${WARNOVERRIDE}
 			if [ "$STRICT" = "true" ]; then
 				STRICT_MODE_VIOLATED=true
 			fi
 		elif [ "$WARNREDUN" = "true" ]; then
-			echo Value of $CFG is redundant by fragment $ORIG_MERGE_FILE:
+			${WARNOVERRIDE} Value of $CFG is redundant by fragment $ORIG_MERGE_FILE:
 		fi
 		if [ "$BUILTIN_FLAG" = "false" ]; then
 			sed -i "/$CFG[ =]/d" $TMP_FILE