1 files changed, 34 insertions, 0 deletions
diff --git a/mk/sub-makefile.mk b/mk/sub-makefile.mk
new file mode 100644
index 0000000000..1e9cf2265d
--- /dev/null
+++ b/mk/sub-makefile.mk
@@ -0,0 +1,34 @@
+# This file is included by all the "stub makefiles" in every directory
+# in the tree except the root.  Its job is to invoke $(MAKE) on the
+# top-level Makefile, but modifying the target so that it applies to
+# the current directory only.
+#
+# eg.
+#  make foo.o  ==>  make -C $(TOP) dir/foo.o
+#  make all    ==>  make -C $(TOP) all_dir
+#  make clean  ==>  make -C $(TOP) clean_dir
+#
+
+# Important, otherwise we get silly built-in rules:
+.SUFFIXES:
+
+TOPMAKE = $(MAKE) -C $(TOP)
+
+default :
+	+$(TOPMAKE) all_$(dir)
+
+# We must not execute multiple recursive invocations of make in parallel.
+.NOTPARALLEL:
+
+# all comes first, we want it to be the default target
+STD_TARGETS = all clean distclean maintainer_clean install
+
+# The + tells make that we're recursively invoking make, otherwise 'make -j2'
+# goes wrong.
+$(STD_TARGETS): 
+	+$(TOPMAKE) $@_$(dir)
+
+OTHERTARGETS=$(filter-out $(STD_TARGETS) $(SPEC_TARGETS),$(MAKECMDGOALS))
+.PHONY: $(OTHERTARGETS)
+$(OTHERTARGETS):
+	+$(TOPMAKE) $(dir)/$@