package/ffmpeg: add optional dependency to harfbuzz

Fixes https://bugs.busybox.net/show_bug.cgi?id=16279

Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/ffmpeg/ffmpeg.mk

@@ -400,6 +400,13 @@ else
 FFMPEG_CONF_OPTS += --disable-fontconfig
 endif
 
+ifeq ($(BR2_PACKAGE_HARFBUZZ),y)
+FFMPEG_CONF_OPTS += --enable-libharfbuzz
+FFMPEG_DEPENDENCIES += harfbuzz
+else
+FFMPEG_CONF_OPTS += --disable-libharfbuzz
+endif
+
 ifeq ($(BR2_PACKAGE_OPENJPEG),y)
 FFMPEG_CONF_OPTS += --enable-libopenjpeg
 FFMPEG_DEPENDENCIES += openjpeg