build: keep recursive dependency check stampfiles up to date

Since the main stamp file depends on the _check stampfile, the _check
stampfile needs to be created on the first run as well.

Fixes spurious rebuilds with CONFIG_AUTOREBUILD=y

Signed-off-by: Felix Fietkau <nbd@nbd.name>

include/package.mk

@@ -156,6 +156,7 @@ define Build/CoreTargets
   $(STAMP_PREPARED): $(STAMP_PREPARED_DEPENDS)
 	@-rm -rf $(PKG_BUILD_DIR)
 	@mkdir -p $(PKG_BUILD_DIR)
+	touch $$@_check
 	$(foreach hook,$(Hooks/Prepare/Pre),$(call $(hook))$(sep))
 	$(Build/Prepare)
 	$(foreach hook,$(Hooks/Prepare/Post),$(call $(hook))$(sep))
@@ -172,6 +173,8 @@ define Build/CoreTargets
 
   $(call Build/Exports,$(STAMP_BUILT))
   $(STAMP_BUILT): $(STAMP_CONFIGURED) $(STAMP_BUILT_DEPENDS)
+	rm -f $$@
+	touch $$@_check
 	$(foreach hook,$(Hooks/Compile/Pre),$(call $(hook))$(sep))
 	$(Build/Compile)
 	$(foreach hook,$(Hooks/Compile/Post),$(call $(hook))$(sep))