--- a/libtiff/Makefile.am
+++ b/libtiff/Makefile.am
@@ -37,8 +37,12 @@
 	tif_win32_versioninfo.rc
 
 libtiffinclude_HEADERS = \
+	tif_config.h \
+	tif_dir.h \
+	tif_hash_set.h \
 	tiff.h \
 	tiffio.h \
+	tiffiop.h \
 	tiffvers.h
 
 if HAVE_CXX
