If you download clang and delete the test directory, you can end up
with the copy line failing with an error, yet the make will complete
successfully. From Greg Clayton!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@140639 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Makefile b/Makefile
index b6c630a..50dcf8c 100644
--- a/Makefile
+++ b/Makefile
@@ -68,7 +68,7 @@
 ifneq ($(PROJ_SRC_ROOT),$(PROJ_OBJ_ROOT))
 $(RecursiveTargets)::
 	$(Verb) for dir in test unittests; do \
-	  if [ ! -f $${dir}/Makefile ]; then \
+	  if [ -f $(PROJ_SRC_DIR)/$${dir}/Makefile ] && [ ! -f $${dir}/Makefile ]; then \
 	    $(MKDIR) $${dir}; \
 	    $(CP) $(PROJ_SRC_DIR)/$${dir}/Makefile $${dir}/Makefile; \
 	  fi \