+#######################
+### Dependency tracking
+
+# Find the file $(1) within the texinfo include dirs and return its path.
+# If not found, i.e. it is a generated file, then the file is ignored.
+find-texi = \
+$(firstword \
+ $(wildcard $(dir $<)$(1)) \
+ $(wildcard $(top-src-dir)/Documentation/$(1)) \
+)
+
+# Recursively scan the file $(1) for @include, search for included files
+# within the texinfo include dirs, and return all dependencies.
+scan-texi = \
+ $(foreach f, $(shell echo | sed -ne "/^@include[[:space:]]/s/@include//p" $(1)), \
+ $(call find-texi,$(f)) \
+ $(call scan-texi,$(call find-texi,$(f))) \
+)
+
+# Find dependencies for the target $@, based on the texinfo source file $<,
+# and write the dependencies to a .dep file.
+DO_TEXI_DEP = ( mkdir -p $(dir $@) && echo ./$@: $(call scan-texi,$<) > $@.dep ) &&
+
+# This is where we import the .dep files so that `make' knows about
+# the various dependencies.
+-include dummy.dep $(wildcard $(OUT)/*.dep) $(wildcard $(OUT)/*/*.dep)
+
+