Fix quoting in default extract command

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/Makefile.package.in

@@ -425,7 +425,8 @@ $(2)_TARGET_CLEAN =		$$($(2)_DIR)/.stamp_cleaned
 $(2)_TARGET_DIRCLEAN =		$$($(2)_DIR)/.stamp_dircleaned
 
 # default extract command
-$(2)_EXTRACT_CMDS ?= $(if $($(2)_SOURCE),$(INFLATE$(suffix $($(2)_SOURCE))) $(DL_DIR)/$($(2)_SOURCE) | \
+$(2)_EXTRACT_CMDS ?= \
+	$$(if $$($(2)_SOURCE),$$(INFLATE$$(suffix $$($(2)_SOURCE))) $(DL_DIR)/$$($(2)_SOURCE) | \
 	$(TAR) $(TAR_STRIP_COMPONENTS)=1 -C $$($(2)_DIR) $(TAR_OPTIONS) -)
 
 # post-steps hooks