+# Determine if '1' is newer than '2'
+TSTAMP = $(if $(wildcard $1),$(shell stat -c %Y $1),0$(info nots: $1))
+NEWER = $(eval 4 := $(call TSTAMP,$(dir $2)$1))
+NEWER += $(eval 5 := $(call TSTAMP,$2))
+NEWER += $(if $(filter $5,$(firstword $(sort $4 $5))),$1,$2)
+