+
+# magic to descend into other directories
+
+obj := .
+old-nested-dirs :=
+
+define push-var
+$(eval save-$2-$1 = $(value $1))
+$(eval $1 :=)
+endef
+
+define pop-var
+$(eval subdir-$2-$1 := $(if $(filter $2,$(save-$2-$1)),$(addprefix $2,$($1))))
+$(eval $1 = $(value save-$2-$1) $$(subdir-$2-$1))
+$(eval save-$2-$1 :=)
+endef
+
+define unnest-dir
+$(foreach var,$(nested-vars),$(call push-var,$(var),$1/))
+$(eval obj := $(obj)/$1)
+$(eval include $(SRC_PATH)/$1/Makefile.objs)
+$(eval obj := $(patsubst %/$1,%,$(obj)))
+$(foreach var,$(nested-vars),$(call pop-var,$(var),$1/))
+endef
+
+define unnest-vars-1
+$(eval nested-dirs := $(filter-out \
+ $(old-nested-dirs), \
+ $(sort $(foreach var,$(nested-vars), $(filter %/, $($(var)))))))
+$(if $(nested-dirs),
+ $(foreach dir,$(nested-dirs),$(call unnest-dir,$(patsubst %/,%,$(dir))))
+ $(eval old-nested-dirs := $(old-nested-dirs) $(nested-dirs))
+ $(call unnest-vars-1))
+endef
+
+define unnest-vars
+$(call unnest-vars-1)
+$(foreach var,$(nested-vars),$(eval $(var) := $(filter-out %/, $($(var)))))
+$(shell mkdir -p $(sort $(foreach var,$(nested-vars),$(dir $($(var))))))
+$(foreach var,$(nested-vars), $(eval \
+ -include $(addsuffix *.d, $(sort $(dir $($(var)))))))
+endef