diff --git a/components/app_trace/component.mk b/components/app_trace/component.mk
index 235f19831d..7a1f39759d 100644
--- a/components/app_trace/component.mk
+++ b/components/app_trace/component.mk
@@ -8,7 +8,7 @@ COMPONENT_ADD_INCLUDEDIRS := include
 
 COMPONENT_ADD_LDFLAGS := -lapp_trace 
 
-ifdef CONFIG_SYSVIEW_ENABLE
+ifeq ("$(CONFIG_SYSVIEW_ENABLE)","y")
 #COMPONENT_EXTRA_INCLUDES := freertos
 
 COMPONENT_ADD_INCLUDEDIRS += \
diff --git a/components/aws_iot/component.mk b/components/aws_iot/component.mk
index cd1b15eeea..aab25a71f3 100644
--- a/components/aws_iot/component.mk
+++ b/components/aws_iot/component.mk
@@ -2,7 +2,7 @@
 # Component Makefile
 #
 
-ifdef CONFIG_AWS_IOT_SDK
+ifeq ("$(CONFIG_AWS_IOT_SDK)","y")
 
 COMPONENT_ADD_INCLUDEDIRS := include aws-iot-device-sdk-embedded-C/include
 
diff --git a/components/bootloader/Makefile.projbuild b/components/bootloader/Makefile.projbuild
index 7a35dc8ad1..db7f4f0a24 100644
--- a/components/bootloader/Makefile.projbuild
+++ b/components/bootloader/Makefile.projbuild
@@ -13,6 +13,7 @@ BOOTLOADER_BUILD_DIR=$(abspath $(BUILD_DIR_BASE)/bootloader)
 BOOTLOADER_BIN=$(BOOTLOADER_BUILD_DIR)/bootloader.bin
 
 # signing key path is resolved relative to the project directory
+CONFIG_SECURE_BOOT_SIGNING_KEY ?=
 SECURE_BOOT_SIGNING_KEY=$(abspath $(call dequote,$(CONFIG_SECURE_BOOT_SIGNING_KEY)))
 export SECURE_BOOT_SIGNING_KEY  # used by bootloader_support component
 
@@ -107,7 +108,7 @@ $(BOOTLOADER_DIGEST_BIN): $(BOOTLOADER_BIN) $(SECURE_BOOTLOADER_KEY)
 	@echo "DIGEST $(notdir $@)"
 	$(Q) $(ESPSECUREPY) digest_secure_bootloader -k $(SECURE_BOOTLOADER_KEY) -o $@ $<
 
-else
+else # CONFIG_SECURE_BOOT_ENABLED && !CONFIG_SECURE_BOOTLOADER_REFLASHABLE && !CONFIG_SECURE_BOOTLOADER_ONE_TIME_FLASH
 bootloader:
 	@echo "Invalid bootloader target: bad sdkconfig?"
 	@exit 1
diff --git a/components/bootloader/subproject/main/component.mk b/components/bootloader/subproject/main/component.mk
index a54fe30a90..633051cb63 100644
--- a/components/bootloader/subproject/main/component.mk
+++ b/components/bootloader/subproject/main/component.mk
@@ -12,7 +12,7 @@ LINKER_SCRIPTS := \
 	$(IDF_PATH)/components/esp32/ld/esp32.peripherals.ld \
 	esp32.bootloader.rom.ld
 
-ifndef CONFIG_SPI_FLASH_ROM_DRIVER_PATCH
+ifneq ("$(CONFIG_SPI_FLASH_ROM_DRIVER_PATCH)","y")
 LINKER_SCRIPTS += $(IDF_PATH)/components/esp32/ld/esp32.rom.spiflash.ld
 endif
 
diff --git a/components/bootloader_support/component.mk b/components/bootloader_support/component.mk
index 6db815afff..8ad21d3b9b 100755
--- a/components/bootloader_support/component.mk
+++ b/components/bootloader_support/component.mk
@@ -12,12 +12,12 @@ COMPONENT_SRCDIRS := src
 #
 # Secure boot signing key support
 #
-ifdef CONFIG_SECURE_BOOT_ENABLED
+ifneq ("$(CONFIG_SECURE_BOOT_ENABLED)","")
 
 # this path is created relative to the component build directory
 SECURE_BOOT_VERIFICATION_KEY := $(abspath signature_verification_key.bin)
 
-ifdef CONFIG_SECURE_BOOT_BUILD_SIGNED_BINARIES
+ifneq ("$(CONFIG_SECURE_BOOT_BUILD_SIGNED_BINARIES)","")
 # verification key derived from signing key.
 $(SECURE_BOOT_VERIFICATION_KEY): $(SECURE_BOOT_SIGNING_KEY) $(SDKCONFIG_MAKEFILE)
 	$(ESPSECUREPY) extract_public_key --keyfile $< $@
diff --git a/components/bt/component.mk b/components/bt/component.mk
index 8f6ce29d51..86fddc8c11 100644
--- a/components/bt/component.mk
+++ b/components/bt/component.mk
@@ -1,7 +1,7 @@
 #
 # Component Makefile
 #
-ifdef CONFIG_BT_ENABLED
+ifneq ("$(CONFIG_BT_ENABLED)","")
 
 COMPONENT_SRCDIRS := .
 
@@ -20,7 +20,7 @@ COMPONENT_SUBMODULES += lib
 endif
 
 
-ifdef CONFIG_BLUEDROID_ENABLED
+ifeq ("$(CONFIG_BLUEDROID_ENABLED)","y")
 
 COMPONENT_ADD_INCLUDEDIRS +=	bluedroid/bta/include			\
 				bluedroid/bta/sys/include		\
diff --git a/components/esp32/Kconfig b/components/esp32/Kconfig
index 86932c3bf8..837a73afad 100644
--- a/components/esp32/Kconfig
+++ b/components/esp32/Kconfig
@@ -846,7 +846,7 @@ config ESP32_WIFI_NVS_ENABLED
 
 endmenu  # Wi-Fi
 
-menu Phy
+menu PHY
 
 config ESP32_PHY_CALIBRATION_AND_DATA_STORAGE
     bool "Do phy calibration and store calibration data in NVS"
diff --git a/components/esp32/component.mk b/components/esp32/component.mk
index a8cd8606c7..a151f81291 100644
--- a/components/esp32/component.mk
+++ b/components/esp32/component.mk
@@ -3,8 +3,9 @@
 #
 
 COMPONENT_SRCDIRS := . hwcrypto
-ifndef CONFIG_NO_BLOBS
-LIBS := core rtc net80211 pp wpa smartconfig coexist wps wpa2 phy
+LIBS ?=
+ifneq ("$(CONFIG_NO_BLOBS)","y")
+LIBS += core rtc net80211 pp wpa smartconfig coexist wps wpa2 phy
 endif
 
 #Linker scripts used to link the final application.
@@ -22,7 +23,7 @@ ifeq ("$(CONFIG_NEWLIB_NANO_FORMAT)","y")
 LINKER_SCRIPTS += esp32.rom.nanofmt.ld
 endif
 
-ifndef CONFIG_SPI_FLASH_ROM_DRIVER_PATCH
+ifneq ("$(CONFIG_SPI_FLASH_ROM_DRIVER_PATCH)","y")
 LINKER_SCRIPTS += esp32.rom.spiflash.ld
 endif
 
diff --git a/components/esptool_py/Makefile.projbuild b/components/esptool_py/Makefile.projbuild
index b35dc11126..dce6b0af28 100644
--- a/components/esptool_py/Makefile.projbuild
+++ b/components/esptool_py/Makefile.projbuild
@@ -6,6 +6,8 @@ ESPFLASHMODE ?= $(CONFIG_ESPTOOLPY_FLASHMODE)
 ESPFLASHFREQ ?= $(CONFIG_ESPTOOLPY_FLASHFREQ)
 ESPFLASHSIZE ?= $(CONFIG_ESPTOOLPY_FLASHSIZE)
 
+CONFIG_ESPTOOLPY_COMPRESSED ?=
+
 PYTHON ?= $(call dequote,$(CONFIG_PYTHON))
 
 # two commands that can be used from other components
diff --git a/components/freertos/component.mk b/components/freertos/component.mk
index 4496355a0e..88be5b8f6d 100644
--- a/components/freertos/component.mk
+++ b/components/freertos/component.mk
@@ -6,6 +6,6 @@ COMPONENT_ADD_LDFLAGS += -Wl,--undefined=uxTopUsedPriority
 COMPONENT_ADD_INCLUDEDIRS := include
 COMPONENT_PRIV_INCLUDEDIRS := include/freertos
 
-#ifdef CONFIG_SYSVIEW_ENABLE
+#ifeq ("$(CONFIG_SYSVIEW_ENABLE)","y")
 #COMPONENT_ADD_INCLUDEDIRS += app_trace
 #endif
diff --git a/components/lwip/component.mk b/components/lwip/component.mk
index 204e94fa72..921cc59166 100644
--- a/components/lwip/component.mk
+++ b/components/lwip/component.mk
@@ -8,8 +8,10 @@ COMPONENT_ADD_INCLUDEDIRS := \
 	include/lwip/posix \
 	apps/ping
 
-ifdef CONFIG_PPP_SUPPORT
+ifeq ("$(CONFIG_PPP_SUPPORT)","y")
 LWIP_PPP_DIRS := netif/ppp/polarssl netif/ppp 
+else
+LWIP_PPP_DIRS :=
 endif
 
 COMPONENT_SRCDIRS := \
diff --git a/components/newlib/component.mk b/components/newlib/component.mk
index 0bf6275bf2..ce5799dfb0 100644
--- a/components/newlib/component.mk
+++ b/components/newlib/component.mk
@@ -1,5 +1,4 @@
 
-
 ifeq ("$(CONFIG_SPIRAM_CACHE_WORKAROUND)","y")
 LIBC_PATH := $(COMPONENT_PATH)/lib/libc-psram-workaround.a
 LIBM_PATH := $(COMPONENT_PATH)/lib/libm-psram-workaround.a
@@ -14,7 +13,7 @@ endif
 
 LIBM_PATH := $(COMPONENT_PATH)/lib/libm.a
 
-endif
+endif  # CONFIG_SPIRAM_CACHE_WORKAROUND
 
 COMPONENT_ADD_LDFLAGS := $(LIBC_PATH) $(LIBM_PATH) -lnewlib
 
diff --git a/examples/protocols/aws_iot/subscribe_publish/main/component.mk b/examples/protocols/aws_iot/subscribe_publish/main/component.mk
index bc11b63933..1ed56547cb 100644
--- a/examples/protocols/aws_iot/subscribe_publish/main/component.mk
+++ b/examples/protocols/aws_iot/subscribe_publish/main/component.mk
@@ -2,7 +2,7 @@
 # Main Makefile. This is basically the same as a component makefile.
 #
 
-ifdef CONFIG_EXAMPLE_EMBEDDED_CERTS
+ifeq ("$(CONFIG_EXAMPLE_EMBEDDED_CERTS)","y")
 # Certificate files. certificate.pem.crt & private.pem.key must be downloaded
 # from AWS, see README for details.
 COMPONENT_EMBED_TXTFILES := certs/aws-root-ca.pem certs/certificate.pem.crt certs/private.pem.key
diff --git a/examples/protocols/aws_iot/thing_shadow/main/component.mk b/examples/protocols/aws_iot/thing_shadow/main/component.mk
index bc11b63933..1ed56547cb 100644
--- a/examples/protocols/aws_iot/thing_shadow/main/component.mk
+++ b/examples/protocols/aws_iot/thing_shadow/main/component.mk
@@ -2,7 +2,7 @@
 # Main Makefile. This is basically the same as a component makefile.
 #
 
-ifdef CONFIG_EXAMPLE_EMBEDDED_CERTS
+ifeq ("$(CONFIG_EXAMPLE_EMBEDDED_CERTS)","y")
 # Certificate files. certificate.pem.crt & private.pem.key must be downloaded
 # from AWS, see README for details.
 COMPONENT_EMBED_TXTFILES := certs/aws-root-ca.pem certs/certificate.pem.crt certs/private.pem.key
diff --git a/make/common.mk b/make/common.mk
index 82652e63d7..358c880889 100644
--- a/make/common.mk
+++ b/make/common.mk
@@ -19,6 +19,7 @@ endif
 #
 # if V=1, $(summary) does nothing and $(details) will echo extra details
 # if V is unset or not 1, $(summary) echoes a summary and $(details) does nothing
+VERBOSE ?=
 V ?= $(VERBOSE)
 ifeq ("$(V)","1")
 summary := @true
@@ -28,7 +29,7 @@ summary := @echo
 details := @true
 
 # disable echoing of commands, directory names
-MAKEFLAGS += --silent
+MAKEFLAGS += --silent --warn-undefined-variables
 endif
 
 # General make utilities
diff --git a/make/component_wrapper.mk b/make/component_wrapper.mk
index f9bdec672f..6184668777 100644
--- a/make/component_wrapper.mk
+++ b/make/component_wrapper.mk
@@ -63,6 +63,13 @@ define compile_only_if_not
 $(eval $(if $(1), $(call compile_exclude, $(2)), $(call compile_include, $(2))))
 endef
 
+COMPONENT_ADD_LINKER_DEPS ?=
+COMPONENT_DEPENDS ?=
+COMPONENT_EXTRA_CLEAN ?=
+COMPONENT_EXTRA_INCLUDES ?=
+COMPONENT_OBJEXCLUDE ?=
+COMPONENT_OBJINCLUDE ?=
+COMPONENT_SUBMODULES ?=
 
 ################################################################################
 # 2) Include the component.mk for the specific component (COMPONENT_MAKEFILE) to
@@ -105,6 +112,7 @@ COMPONENT_EMBED_OBJS ?= $(addsuffix .bin.o,$(notdir $(COMPONENT_EMBED_FILES))) $
 # variable with all the include dirs from all the components in random order. This
 # means we can accidentally grab a header from another component before grabbing our own.
 # To make sure that does not happen, re-order the includes so ours come first.
+COMPONENT_PRIV_INCLUDEDIRS ?=
 OWN_INCLUDES:=$(abspath $(addprefix $(COMPONENT_PATH)/,$(COMPONENT_PRIV_INCLUDEDIRS) $(COMPONENT_ADD_INCLUDEDIRS)))
 COMPONENT_INCLUDES := $(OWN_INCLUDES) $(filter-out $(OWN_INCLUDES),$(COMPONENT_INCLUDES))
 
@@ -139,7 +147,7 @@ endef
 # component-specific feature, please don't! What you want is a
 # Makefile.projbuild for your component (see docs/build-system.rst for
 # more.)
-component_project_vars.mk::
+component_project_vars.mk:
 	$(details) "Building component project variables list $(abspath $@)"
 	@echo '# Automatically generated build file. Do not edit.' > $@
 	@echo 'COMPONENT_INCLUDES += $(call MakeVariablePath,$(addprefix $(COMPONENT_PATH)/,$(COMPONENT_ADD_INCLUDEDIRS)))' >> $@
@@ -178,6 +186,8 @@ clean:
 	rm -f $(CLEAN_FILES)
 endif
 
+DEBUG_FLAGS ?= -ggdb
+
 # Include all dependency files already generated
 -include $(COMPONENT_OBJS:.o=.d)
 
diff --git a/make/project.mk b/make/project.mk
index d22a1b1dd0..31635d41d0 100644
--- a/make/project.mk
+++ b/make/project.mk
@@ -56,6 +56,7 @@ $(error esp-idf build system doesn't support running 'clean' targets along with
 endif
 endif
 
+OS ?=
 
 # make IDF_PATH a "real" absolute path
 # * works around the case where a shell character is embedded in the environment variable value.
@@ -113,6 +114,7 @@ export BUILD_DIR_BASE
 # or the directory contains subdirectories which are components.)
 # The project Makefile can override these component dirs, or add extras via EXTRA_COMPONENT_DIRS
 ifndef COMPONENT_DIRS
+EXTRA_COMPONENT_DIRS ?=
 COMPONENT_DIRS := $(PROJECT_PATH)/components $(EXTRA_COMPONENT_DIRS) $(IDF_PATH)/components $(PROJECT_PATH)/main
 endif
 export COMPONENT_DIRS
@@ -146,15 +148,18 @@ export COMPONENTS
 COMPONENT_PATHS := $(foreach comp,$(COMPONENTS),$(firstword $(foreach cd,$(COMPONENT_DIRS),$(wildcard $(dir $(cd))$(comp) $(cd)/$(comp)))))
 
 # If TESTS_ALL set to 1, set TEST_COMPONENTS_LIST to all components
+ifdef TESTS_ALL
 ifeq ($(TESTS_ALL),1)
 TEST_COMPONENTS_LIST := $(COMPONENTS)
 else
 # otherwise, use TEST_COMPONENTS
 TEST_COMPONENTS_LIST := $(TEST_COMPONENTS)
 endif
+else
+TEST_COMPONENTS_LIST :=
+endif
 TEST_COMPONENT_PATHS := $(foreach comp,$(TEST_COMPONENTS_LIST),$(firstword $(foreach dir,$(COMPONENT_DIRS),$(wildcard $(dir)/$(comp)/test))))
-TEST_COMPONENT_NAMES :=  $(foreach comp,$(TEST_COMPONENT_PATHS),$(lastword $(subst /, ,$(dir $(comp))))_test)
-
+TEST_COMPONENT_NAMES := $(foreach comp,$(TEST_COMPONENT_PATHS),$(lastword $(subst /, ,$(dir $(comp))))_test)
 
 # Initialise project-wide variables which can be added to by
 # each component.
@@ -189,9 +194,9 @@ export COMPONENT_INCLUDES
 include $(IDF_PATH)/make/common.mk
 
 all:
-ifdef CONFIG_SECURE_BOOT_ENABLED
+ifneq ("$(CONFIG_SECURE_BOOT_ENABLED)","")
 	@echo "(Secure boot enabled, so bootloader not flashed automatically. See 'make bootloader' output)"
-ifndef CONFIG_SECURE_BOOT_BUILD_SIGNED_BINARIES
+ifeq ("$(CONFIG_SECURE_BOOT_BUILD_SIGNED_BINARIES)","")
 	@echo "App built but not signed. Sign app & partition data before flashing, via espsecure.py:"
 	@echo "espsecure.py sign_data --keyfile KEYFILE $(APP_BIN)"
 	@echo "espsecure.py sign_data --keyfile KEYFILE $(PARTITION_TABLE_BIN)"
@@ -206,6 +211,7 @@ endif
 IDF_VER := $(shell cd ${IDF_PATH} && git describe --always --tags --dirty)
 
 # Set default LDFLAGS
+EXTRA_LDFLAGS ?=
 LDFLAGS ?= -nostdlib \
 	-u call_user_start_cpu0	\
 	$(EXTRA_LDFLAGS) \
@@ -228,6 +234,8 @@ LDFLAGS ?= -nostdlib \
 
 # CPPFLAGS used by C preprocessor
 # If any flags are defined in application Makefile, add them at the end. 
+CPPFLAGS ?=
+EXTRA_CPPFLAGS ?=
 CPPFLAGS := -DESP_PLATFORM -D IDF_VER=\"$(IDF_VER)\" -MMD -MP $(CPPFLAGS) $(EXTRA_CPPFLAGS)
 
 # Warnings-related flags relevant both for C and C++
@@ -263,6 +271,8 @@ DEBUG_FLAGS ?= -ggdb
 
 # List of flags to pass to C compiler
 # If any flags are defined in application Makefile, add them at the end.
+CFLAGS ?=
+EXTRA_CFLAGS ?=
 CFLAGS := $(strip \
 	-std=gnu99 \
 	$(OPTIMIZATION_FLAGS) $(DEBUG_FLAGS) \
@@ -273,6 +283,8 @@ CFLAGS := $(strip \
 
 # List of flags to pass to C++ compiler
 # If any flags are defined in application Makefile, add them at the end.
+CXXFLAGS ?=
+EXTRA_CXXFLAGS ?=
 CXXFLAGS := $(strip \
 	-std=gnu++11 \
 	-fno-exceptions \
@@ -289,8 +301,16 @@ export CFLAGS CPPFLAGS CXXFLAGS
 HOSTCC := $(CC)
 HOSTLD := $(LD)
 HOSTAR := $(AR)
+ifdef OBJCOPY
 HOSTOBJCOPY := $(OBJCOPY)
+else
+HOSTOBJCOPY := objcopy
+endif
+ifdef SIZE
 HOSTSIZE := $(SIZE)
+else
+HOSTSIZE := size
+endif
 export HOSTCC HOSTLD HOSTAR HOSTOBJCOPY SIZE
 
 # Set target compiler. Defaults to whatever the user has
@@ -333,6 +353,7 @@ endif
 #
 # also depends on additional dependencies (linker scripts & binary libraries)
 # stored in COMPONENT_LINKER_DEPS, built via component.mk files' COMPONENT_ADD_LINKER_DEPS variable
+COMPONENT_LINKER_DEPS ?=
 $(APP_ELF): $(foreach libcomp,$(COMPONENT_LIBRARIES),$(BUILD_DIR_BASE)/$(libcomp)/lib$(libcomp).a) $(COMPONENT_LINKER_DEPS) $(COMPONENT_PROJECT_VARS)
 	$(summary) LD $(patsubst $(PWD)/%,%,$@)
 	$(CC) $(LDFLAGS) -o $@ -Wl,-Map=$(APP_MAP)
@@ -434,7 +455,7 @@ check-submodules: $(IDF_PATH)/$(1)/.git
 $(IDF_PATH)/$(1)/.git:
 	@echo "WARNING: Missing submodule $(1)..."
 	[ -e ${IDF_PATH}/.git ] || ( echo "ERROR: esp-idf must be cloned from git to work."; exit 1)
-	[ -x $(which git) ] || ( echo "ERROR: Need to run 'git submodule init $(1)' in esp-idf root directory."; exit 1)
+	[ -x $$(which git) ] || ( echo "ERROR: Need to run 'git submodule init $(1)' in esp-idf root directory."; exit 1)
 	@echo "Attempting 'git submodule update --init $(1)' in esp-idf root directory..."
 	cd ${IDF_PATH} && git submodule update --init $(1)
 
diff --git a/make/project_config.mk b/make/project_config.mk
index c92d5292ef..0a212cd287 100644
--- a/make/project_config.mk
+++ b/make/project_config.mk
@@ -16,8 +16,8 @@ SDKCONFIG ?= $(PROJECT_PATH)/sdkconfig
 SDKCONFIG_DEFAULTS ?= $(PROJECT_PATH)/sdkconfig.defaults
 
 # reset MAKEFLAGS as the menuconfig makefile uses implicit compile rules
-$(KCONFIG_TOOL_DIR)/mconf $(KCONFIG_TOOL_DIR)/conf:
-	MAKEFLAGS=$(ORIGINAL_MAKEFLAGS) CC=$(HOSTCC) LD=$(HOSTLD) \
+$(KCONFIG_TOOL_DIR)/mconf $(KCONFIG_TOOL_DIR)/conf: $(wildcard $(KCONFIG_TOOL_DIR)/*.c)
+	MAKEFLAGS="" CC=$(HOSTCC) LD=$(HOSTLD) \
 	$(MAKE) -C $(KCONFIG_TOOL_DIR)
 
 ifeq ("$(wildcard $(SDKCONFIG))","")
@@ -42,7 +42,7 @@ define RunConf
 	$(KCONFIG_TOOL_DIR)/$1 $(IDF_PATH)/Kconfig
 endef
 
-ifeq ("$(MAKE_RESTARTS)","")
+ifndef MAKE_RESTARTS
 # menuconfig, defconfig and "GENCONFIG" configuration generation only
 # ever run on the first make pass, subsequent passes don't run these
 # (make often wants to re-run them as the conf tool can regenerate the
@@ -92,6 +92,6 @@ endif
 
 .PHONY: config-clean defconfig menuconfig
 config-clean:
-	$(summary RM CONFIG)
-	$(MAKE) -C $(KCONFIG_TOOL_DIR) clean
+	$(summary) RM CONFIG
+	MAKEFLAGS="" $(MAKE) -C $(KCONFIG_TOOL_DIR) clean
 	rm -rf $(BUILD_DIR_BASE)/include/config $(BUILD_DIR_BASE)/include/sdkconfig.h
diff --git a/tools/kconfig/.gitignore b/tools/kconfig/.gitignore
index 977c274ce3..1950c8cb1b 100644
--- a/tools/kconfig/.gitignore
+++ b/tools/kconfig/.gitignore
@@ -2,6 +2,7 @@
 # Generated files
 #
 config*
+*.d
 *.lex.c
 *.tab.c
 *.tab.h
diff --git a/tools/kconfig/Makefile b/tools/kconfig/Makefile
index 9680b74109..c421365f2e 100644
--- a/tools/kconfig/Makefile
+++ b/tools/kconfig/Makefile
@@ -145,7 +145,7 @@ check-lxdialog  := lxdialog/check-lxdialog.sh
 # Use recursively expanded variables so we do not call gcc unless
 # we really need to do so. (Do not call gcc as part of make mrproper)
 CFLAGS += $(shell $(CONFIG_SHELL) $(check-lxdialog) -ccflags) \
-                    -DLOCALE
+                    -DLOCALE -MD
 
 # ===========================================================================
 # Shared Makefile for the various kconfig executables:
@@ -173,7 +173,7 @@ gconf-objs	:= gconf.o zconf.tab.o
 
 hostprogs-y := conf nconf mconf kxgettext qconf gconf
 
-clean-files	:= qconf.moc .tmp_qtcheck .tmp_gtkcheck
+clean-files	:= qconf.moc .tmp_qtcheck .tmp_gtkcheck *.d
 clean-files	+= zconf.tab.c zconf.lex.c zconf.hash.c gconf.glade.h
 clean-files += $(conf-objs) $(mconf-objs) conf mconf $(lxdialog)
 
@@ -309,3 +309,6 @@ zconf.tab.c: zconf.y
 
 clean: 
 	rm -f $(clean-files)
+
+-include $(wildcard *.d)
+-include $(wildcard lxdialog/*.d)
diff --git a/tools/kconfig/confdata.c b/tools/kconfig/confdata.c
index 1e3d1f35b2..2a8d5b54d6 100644
--- a/tools/kconfig/confdata.c
+++ b/tools/kconfig/confdata.c
@@ -141,7 +141,7 @@ static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p)
 			sym->flags |= def_flags;
 			break;
 		}
-		if (p[0] == 'n') {
+		if (p[0] == 'n' || p[0] == '\0') {
 			sym->def[def].tri = no;
 			sym->flags |= def_flags;
 			break;
@@ -490,12 +490,7 @@ kconfig_print_symbol(FILE *fp, struct symbol *sym, const char *value, void *arg)
 	case S_BOOLEAN:
 	case S_TRISTATE:
 		if (*value == 'n') {
-			bool skip_unset = (arg != NULL);
-
-			if (!skip_unset)
-				fprintf(fp, "# %s%s is not set\n",
-				    CONFIG_, sym->name);
-			return;
+			value = "";
 		}
 		break;
 	default:
@@ -986,17 +981,21 @@ int conf_write_autoconf(void)
 
 	conf_write_heading(out_h, &header_printer_cb, NULL);
 
+	/* write symbols to auto.conf, tristate and header files */
 	for_all_symbols(i, sym) {
-		sym_calc_value(sym);
-		if (!(sym->flags & SYMBOL_WRITE) || !sym->name)
-			continue;
-
-		/* write symbol to auto.conf, tristate and header files */
-		conf_write_symbol(out, sym, &kconfig_printer_cb, (void *)1);
-
-		conf_write_symbol(tristate, sym, &tristate_printer_cb, (void *)1);
-
-		conf_write_symbol(out_h, sym, &header_printer_cb, NULL);
+		if (!sym->name) continue;
+		if ((sym->flags & SYMBOL_WRITE) ||
+		    /*
+		     * If the symbol is disabled by dependency we still want it in auto.conf
+		     * so that all possible variables are always defined.
+		     */
+		    (sym->dir_dep.expr != NULL && sym->dir_dep.tri == no)) {
+			conf_write_symbol(out, sym, &kconfig_printer_cb, NULL);
+		}
+		if (sym->flags & SYMBOL_WRITE) {
+			conf_write_symbol(tristate, sym, &tristate_printer_cb, NULL);
+			conf_write_symbol(out_h, sym, &header_printer_cb, NULL);
+		}
 	}
 	fclose(out);
 	fclose(tristate);