Merge branch 'bugfix/make_clean_kconfig' into 'master'

Don't try to clean the old kconfig tools on Unix

See merge request espressif/esp-idf!6855

make/project_config.mk

@@ -173,6 +173,8 @@ endif
 .PHONY: config-clean defconfig menuconfig
 config-clean:
 	$(summary) RM CONFIG
+ifeq ($(OS),Windows_NT)
 	MAKEFLAGS="" $(MAKE) -C $(KCONFIG_TOOL_DIR) clean
+endif
 	rm -rf $(BUILD_DIR_BASE)/include/config $(BUILD_DIR_BASE)/include/sdkconfig.h \
 		$(COMPONENT_KCONFIGS_SOURCE_FILE) $(COMPONENT_KCONFIGS_PROJBUILD_SOURCE_FILE)