export private headers for freeimage
--- i/libtiff/Makefile.am
+++ w/libtiff/Makefile.am
@@ -36,8 +36,12 @@ EXTRA_DIST = \
 	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