nftables: implement no/json variants

Replace the build time choice of json support with a package based
choice.  Users requiring a json aware version of 'nft' may now install
nftables-json.

The default choice to fulfill the 'nftables' package dependency is
'nftables-nojson'

Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>

package/network/utils/nftables/Makefile

@@ -13,7 +13,7 @@ PKG_RELEASE:=1
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
 PKG_SOURCE_URL:=https://netfilter.org/projects/$(PKG_NAME)/files
 PKG_HASH:=956b915ce2a7aeaff123e49006be7a0690a0964e96c062703181a36e2e5edb78
-PKG_MAINTAINER:=Steven Barth <steven@midlink.org>
+PKG_MAINTAINER:=
 PKG_LICENSE:=GPL-2.0
 
 PKG_FIXUP:=autoreconf
@@ -28,33 +28,45 @@ CONFIGURE_ARGS += \
         --disable-man-doc \
         --with-mini-gmp \
         --without-cli \
-        --disable-python \
+        --disable-python
 
-define Package/nftables
+define Package/nftables/Default
   SECTION:=net
   CATEGORY:=Network
   SUBMENU:=Firewall
-  TITLE:=nftables packet filtering userspace utility
-  DEPENDS:=+kmod-nft-core +libnftnl +PACKAGE_NFT_WITH_JSON:jansson
+  TITLE:=nftables userspace utility
+  DEPENDS:=+kmod-nft-core +libnftnl
   URL:=http://netfilter.org/projects/nftables/
+  PROVIDES:=nftables
 endef
 
-define Package/nftables/config
-	config PACKAGE_NFT_WITH_JSON
-		bool "Build nftables with json support"
-		depends on PACKAGE_nftables
-		default n
+define Package/nftables-nojson
+  $(Package/nftables/Default)
+  TITLE+= no JSON support
+  VARIANT:=nojson
+  DEFAULT_VARIANT:=1
 endef
 
-ifeq ($(CONFIG_PACKAGE_NFT_WITH_JSON),y)
-CONFIGURE_ARGS += --with-json
+define Package/nftables-json
+  $(Package/nftables/Default)
+  TITLE+= with JSON support
+  VARIANT:=json
+  DEPENDS+=+jansson
+endef
+
+ifeq ($(BUILD_VARIANT),json)
+  CONFIGURE_ARGS += --with-json
 endif
 
-define Package/nftables/install
+define Package/nftables/install/Default
 	$(INSTALL_DIR) $(1)/usr/sbin
 	$(CP) $(PKG_INSTALL_DIR)/usr/sbin/nft $(1)/usr/sbin/
 	$(INSTALL_DIR) $(1)/usr/lib
 	$(CP) $(PKG_INSTALL_DIR)/usr/lib/*.so* $(1)/usr/lib/
 endef
 
-$(eval $(call BuildPackage,nftables))
+Package/nftables-nojson/install = $(Package/nftables/install/Default)
+Package/nftables-json/install = $(Package/nftables/install/Default)
+
+$(eval $(call BuildPackage,nftables-nojson))
+$(eval $(call BuildPackage,nftables-json))