If the source tree's Makefile is more up-to-date, copy it over into the build
tree.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@9836 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Makefile.rules b/Makefile.rules
index af0c021..4702534 100644
--- a/Makefile.rules
+++ b/Makefile.rules
@@ -816,6 +816,12 @@
@${ECHO} "****************************************************************"
$(VERB) exit 1
+# If the Makefile in the source tree has been updated, copy it over into the
+# build tree.
+Makefile :: $(BUILD_SRC_DIR)/Makefile
+ @${ECHO} "===== Makefile out of date, updating from source dir: `dirname $<` ====="
+ cp -f $< $@
+
#
# Include dependencies generated from C/C++ source files, but not if we
# are cleaning (this example taken from the GNU Make Manual).