make `make` work in examples/PrintFucntionNames on Mac. I checked that it still works on Linux.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@124325 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/examples/PrintFunctionNames/Makefile b/examples/PrintFunctionNames/Makefile
index 125ac48..23a5305 100644
--- a/examples/PrintFunctionNames/Makefile
+++ b/examples/PrintFunctionNames/Makefile
@@ -18,7 +18,11 @@
 endif
 endif
 
-LINK_LIBS_IN_SHARED = 1
+LINK_LIBS_IN_SHARED = 0
 SHARED_LIBRARY = 1
 
 include $(CLANG_LEVEL)/Makefile
+
+ifeq ($(OS),Darwin)
+  LDFLAGS=-Wl,-undefined,dynamic_lookup
+endif