-# Now smash together user's values with our extra values
-FINAL_CFLAGS = $(CFLAGS) $(WARN_CFLAGS) $(CONFIGURE_CFLAGS) $(extra_cflags)
-FINAL_CXXFLAGS = $(CXXFLAGS) $(WARN_CXXFLAGS) $(CONFIGURE_CXXFLAGS) $(extra_cflags) $(extra_cxxflags)
-FINAL_LDFLAGS = $(LDFLAGS) $(CONFIGURE_LDFLAGS)
+# Get settings from the output of configure by running it to generate
+# Makefile.config if it doesn't exist yet.
+
+# If Makefile.config doesn't exist, then srcdir won't be
+# set. Conditionally set it (assuming a plain srcdir build) so that
+# the rule to generate Makefile.config can actually work.
+srcdir ?= .
+
+include Makefile.config
+
+# We make all targets depend on the Makefiles themselves.
+global_deps = Makefile Makefile.config Makefile.local \
+ $(subdirs:%=%/Makefile) $(subdirs:%=%/Makefile.local)
+
+INCLUDE_MORE := yes
+ifneq ($(filter clean distclean dataclean, $(word 1, $(MAKECMDGOALS))),)
+CLEAN_GOAL := $(word 1, $(MAKECMDGOALS))
+
+# If there are more goals following CLEAN_GOAL, run $(MAKE)s in parts.
+ifneq ($(word 2, $(MAKECMDGOALS)),)
+INCLUDE_MORE := no
+FOLLOWING_GOALS := $(wordlist 2, 99, $(MAKECMDGOALS))
+
+.PHONY: $(FOLLOWING_GOALS) make_in_parts
+$(FOLLOWING_GOALS):
+ @true
+$(CLEAN_GOAL): make_in_parts
+make_in_parts:
+ $(MAKE) $(CLEAN_GOAL)
+ $(MAKE) $(FOLLOWING_GOALS) configure_options="$(configure_options)"
+endif