diff --git a/src/Makefile.am b/src/Makefile.am
index c4e2e37e..e1c1f872 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,7 +1,8 @@
 AM_CPPFLAGS = -I$(top_buildir)/src
 lib_LTLIBRARIES = libwebpdecode.la
 
-libwebpdecode_la_SOURCES = webp/decode.h webp/vp8.h \
+libwebpdecode_la_SOURCES = \
+  webp/decode.h webp/decode_vp8.h webp/types.h \
   dec/bits.h dec/vp8i.h dec/yuv.h dec/bits.c dec/dsp.c dec/frame.c \
   dec/quant.c dec/tree.c dec/vp8.c dec/webp.c dec/yuv.c
 libwebpdecode_la_LDFLAGS = -version-info 0:0:0