zstd: build program and add menuconfig entry for host variant

The zstd (de)compression tool may be used in post-image scripts to
compress certain elements of the final image.

In order to allow that, make host-zstd selectable in the 'Host
utilities' menu, and build the binary in addition to the library.

Signed-off-by: Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/Config.in.host

@@ -62,5 +62,6 @@ menu "Host utilities"
 	source "package/vboot-utils/Config.in.host"
 	source "package/xorriso/Config.in.host"
 	source "package/zip/Config.in.host"
+	source "package/zstd/Config.in.host"
 
 endmenu

package/zstd/Config.in.host

@@ -0,0 +1,8 @@
+config BR2_PACKAGE_HOST_ZSTD
+	bool "host zstd"
+	help
+	  Zstandard, or zstd as short version, is a fast lossless
+	  compression algorithm, targeting real-time compression
+	  scenarios at zlib-level and better compression ratios
+
+	  https://facebook.github.io/zstd

package/zstd/zstd.mk

@@ -72,11 +72,15 @@ endef
 define HOST_ZSTD_BUILD_CMDS
 	$(HOST_MAKE_ENV) $(HOST_CONFIGURE_OPTS) $(MAKE) \
 		-C $(@D)/lib
+	$(HOST_MAKE_ENV) $(HOST_CONFIGURE_OPTS) $(MAKE) \
+		-C $(@D) zstd
 endef
 
 define HOST_ZSTD_INSTALL_CMDS
 	$(HOST_MAKE_ENV) $(HOST_CONFIGURE_OPTS) $(MAKE) \
 		DESTDIR=$(HOST_DIR) PREFIX=/usr -C $(@D)/lib install
+	$(HOST_MAKE_ENV) $(HOST_CONFIGURE_OPTS) $(MAKE) \
+		DESTDIR=$(HOST_DIR) PREFIX=/usr -C $(@D)/programs install
 endef
 
 $(eval $(generic-package))