diff --git a/ion/Makefile b/ion/Makefile
index 4182a9224..96797fba2 100644
--- a/ion/Makefile
+++ b/ion/Makefile
@@ -34,6 +34,7 @@ ion_src += $(addprefix ion/src/shared/, \
   rtc.cpp \
   stack_position.cpp \
   storage.cpp \
+  internal_storage.cpp \
   unicode/utf8_decoder.cpp\
   unicode/utf8_helper.cpp\
 )