fix unnecessary kernel package recompile

SVN-Revision: 5227

include/package.mk

@@ -256,16 +256,18 @@ define BuildPackage
 
   $$(eval $$(call Build/DefaultTargets,$(1)))
 
-  ifneq ($$(CONFIG_PACKAGE_$(1)),)
-    ifneq ($(MAKECMDGOALS),prereq)
-      ifneq ($(DUMP),1)
-        ifneq ($$(shell $(SCRIPT_DIR)/timestamp.pl -p -x ipkg -x ipkg-install '$$(IPKG_$(1))' '$(PKG_BUILD_DIR)'),$$(IPKG_$(1)))
-          _INFO+=$(subst $(TOPDIR)/,,$$(IPKG_$(1)))
-          $(PKG_BUILD_DIR)/.built: package-rebuild
-        endif
-
-        ifneq ($$(_INFO),)
-          $$(info Rebuilding $$(_INFO))
+  ifdef Package/$(1)/install
+    ifneq ($$(CONFIG_PACKAGE_$(1)),)
+      ifneq ($(MAKECMDGOALS),prereq)
+        ifneq ($(DUMP),1)
+          ifneq ($$(shell $(SCRIPT_DIR)/timestamp.pl -p -x ipkg -x ipkg-install '$$(IPKG_$(1))' '$(PKG_BUILD_DIR)'),$$(IPKG_$(1)))
+            _INFO+=$(subst $(TOPDIR)/,,$$(IPKG_$(1)))
+            $(PKG_BUILD_DIR)/.built: package-rebuild
+          endif
+
+          ifneq ($$(_INFO),)
+            $$(info Rebuilding $$(_INFO))
+          endif
         endif
       endif
     endif