diff --git a/src/Makefile.am b/src/Makefile.am
index c3eb4747..718fbe2f 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -66,6 +66,8 @@ libmu_la_SOURCES=			\
 	mu-maildir.h			\
 	mu-msg-contact.c		\
 	mu-msg-contact.h		\
+	mu-msg-data.c			\
+	mu-msg-data.h			\
 	mu-msg-fields.c			\
 	mu-msg-fields.h			\
 	mu-msg-flags.c			\