whetstone: use the <pkg>_EXTRACT_CMDS mechanism

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/whetstone/whetstone.mk

@@ -8,6 +8,10 @@ WHETSTONE_VERSION = 1.2
 WHETSTONE_SOURCE = whetstone.c
 WHETSTONE_SITE = http://www.netlib.org/benchmark/
 
+define WHETSTONE_EXTRACT_CMDS
+	cp $(DL_DIR)/$($(PKG)_SOURCE) $(@D)/
+endef
+
 define WHETSTONE_BUILD_CMDS
 	$(TARGET_CONFIGURE_OPTS) $(MAKE) LDLIBS="-lm" -C $(@D) whetstone
 endef
@@ -25,9 +29,3 @@ define WHETSTONE_UNINSTALL_TARGET_CMDS
 endef
 
 $(eval $(call GENTARGETS))
-
-$(BUILD_DIR)/whetstone-$(WHETSTONE_VERSION)/.stamp_extracted:
-	@$(call MESSAGE,"Extracting")
-	$(Q)mkdir -p $(@D)
-	$(Q)cp $(DL_DIR)/$($(PKG)_SOURCE) $(@D)/
-	$(Q)touch $@