Got test_decoder working!

tools/make_cmakelists.py

diff --git a/tools/make_cmakelists.py b/tools/make_cmakelists.py
index b8f46b9..2b426b5 100755
--- a/tools/make_cmakelists.py
+++ b/tools/make_cmakelists.py
@@ -120,6 +120,9 @@
   def upb_proto_library(self, **kwargs):
     pass
 
+  def upb_proto_reflection_library(self, **kwargs):
+    pass
+
   def genrule(self, **kwargs):
     pass