diff --git a/src/enc/Makefile.am b/src/enc/Makefile.am
index 20ccb4c8..276233e2 100644
--- a/src/enc/Makefile.am
+++ b/src/enc/Makefile.am
@@ -4,6 +4,7 @@ libwebpencode_la_SOURCES =
 libwebpencode_la_SOURCES += alpha.c
 libwebpencode_la_SOURCES += analysis.c
 libwebpencode_la_SOURCES += backward_references.c
+libwebpencode_la_SOURCES += backward_references.h
 libwebpencode_la_SOURCES += config.c
 libwebpencode_la_SOURCES += cost.c
 libwebpencode_la_SOURCES += cost.h
@@ -12,6 +13,7 @@ libwebpencode_la_SOURCES += delta_palettization.h
 libwebpencode_la_SOURCES += filter.c
 libwebpencode_la_SOURCES += frame.c
 libwebpencode_la_SOURCES += histogram.c
+libwebpencode_la_SOURCES += histogram.h
 libwebpencode_la_SOURCES += iterator.c
 libwebpencode_la_SOURCES += near_lossless.c
 libwebpencode_la_SOURCES += picture.c
@@ -25,6 +27,7 @@ libwebpencode_la_SOURCES += token.c
 libwebpencode_la_SOURCES += tree.c
 libwebpencode_la_SOURCES += vp8enci.h
 libwebpencode_la_SOURCES += vp8l.c
+libwebpencode_la_SOURCES += vp8li.h
 libwebpencode_la_SOURCES += webpenc.c
 
 libwebpencodeinclude_HEADERS =