package: use the generic _HELP_CMDS for kconfig-based packages

As Thomas put it:

    The <pkg>_HELP_CMDS variable allows packages using the
    kconfig-package infrastructure to display their specific
    targets related to the handling of their configuration.

    However, it was not consistently used and handled by the
    different packages.

So, this commit switches all the kconfig-based package to use the
generic help helper.

As a consequence:

  - all kconfig packages now advetise their kconfig-related actions,
    where some were previously missing: at91bootstrap3, linux-backports,
    swupdate, xvisor;

  - busybox advertises it does not support defconfig files;

  - the 'foo-savedfconfig' action is no longer advertised: it is to be
    considered an internal implementation detail.
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

buildroot-2021.05/boot/barebox/barebox/barebox.mk

@@ -4,10 +4,5 @@
 #
 ################################################################################
 
-define BAREBOX_HELP_CMDS
-	@echo '  barebox-menuconfig     - Run barebox menuconfig'
-	@echo '  barebox-savedefconfig  - Run barebox savedefconfig'
-endef
-
 # Instantiate the barebox package
 $(eval $(barebox-package))

buildroot-2021.05/boot/uboot/uboot.mk

@@ -292,12 +292,6 @@ UBOOT_KCONFIG_EDITORS = menuconfig xconfig gconfig nconfig
 # override again. In addition, host-ccache is not ready at kconfig
 # time, so use HOSTCC_NOCCACHE.
 UBOOT_KCONFIG_OPTS = $(UBOOT_MAKE_OPTS) HOSTCC="$(HOSTCC_NOCCACHE)" HOSTLDFLAGS=""
-define UBOOT_HELP_CMDS
-	@echo '  uboot-menuconfig       - Run U-Boot menuconfig'
-	@echo '  uboot-savedefconfig    - Run U-Boot savedefconfig'
-	@echo '  uboot-update-defconfig - Save the U-Boot configuration to the path specified'
-	@echo '                             by BR2_TARGET_UBOOT_CUSTOM_CONFIG_FILE'
-endef
 endif # BR2_TARGET_UBOOT_BUILD_SYSTEM_LEGACY
 
 UBOOT_CUSTOM_DTS_PATH = $(call qstrip,$(BR2_TARGET_UBOOT_CUSTOM_DTS_PATH))

buildroot-2021.05/linux/linux.mk

@@ -16,13 +16,6 @@ LINUX_CPE_ID_VENDOR = linux
 LINUX_CPE_ID_PRODUCT = linux_kernel
 LINUX_CPE_ID_PREFIX = cpe:2.3:o
 
-define LINUX_HELP_CMDS
-	@echo '  linux-menuconfig       - Run Linux kernel menuconfig'
-	@echo '  linux-savedefconfig    - Run Linux kernel savedefconfig'
-	@echo '  linux-update-defconfig - Save the Linux configuration to the path specified'
-	@echo '                             by BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE'
-endef
-
 # Compute LINUX_SOURCE and LINUX_SITE from the configuration
 ifeq ($(BR2_LINUX_KERNEL_CUSTOM_TARBALL),y)
 LINUX_TARBALL = $(call qstrip,$(BR2_LINUX_KERNEL_CUSTOM_TARBALL_LOCATION))

buildroot-2021.05/package/busybox/busybox.mk

@@ -11,10 +11,6 @@ BUSYBOX_LICENSE = GPL-2.0, bzip2-1.0.4
 BUSYBOX_LICENSE_FILES = LICENSE archival/libarchive/bz/LICENSE
 BUSYBOX_CPE_ID_VENDOR = busybox
 
-define BUSYBOX_HELP_CMDS
-	@echo '  busybox-menuconfig     - Run BusyBox menuconfig'
-endef
-
 BUSYBOX_CFLAGS = \
 	$(TARGET_CFLAGS)
 
@@ -107,6 +103,7 @@ ifndef BUSYBOX_CONFIG_FILE
 BUSYBOX_CONFIG_FILE = $(call qstrip,$(BR2_PACKAGE_BUSYBOX_CONFIG))
 endif
 
+BUSYBOX_KCONFIG_HAS_DEFCONFIG = NO
 BUSYBOX_KCONFIG_FILE = $(BUSYBOX_CONFIG_FILE)
 BUSYBOX_KCONFIG_FRAGMENT_FILES = $(call qstrip,$(BR2_PACKAGE_BUSYBOX_CONFIG_FRAGMENT_FILES))
 BUSYBOX_KCONFIG_EDITORS = menuconfig xconfig gconfig

buildroot-2021.05/package/uclibc/uclibc.mk

@@ -13,10 +13,6 @@ UCLIBC_INSTALL_STAGING = YES
 UCLIBC_CPE_ID_VENDOR = uclibc-ng_project
 UCLIBC_CPE_ID_PRODUCT = uclibc-ng
 
-define UCLIBC_HELP_CMDS
-	@echo '  uclibc-menuconfig      - Run uClibc menuconfig'
-endef
-
 # uclibc is part of the toolchain so disable the toolchain dependency
 UCLIBC_ADD_TOOLCHAIN_DEPENDENCY = NO