libavfilter/Makefile: add forgotten entries for the ff-sinks

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavfilter/Makefile

@@ -76,6 +76,7 @@ OBJS-$(CONFIG_ANULLSRC_FILTER)               += asrc_anullsrc.o
 OBJS-$(CONFIG_FLITE_FILTER)                  += asrc_flite.o
 
 OBJS-$(CONFIG_ABUFFERSINK_FILTER)            += sink_buffer.o
+OBJS-$(CONFIG_FFABUFFERSINK_FILTER)          += sink_buffer.o
 OBJS-$(CONFIG_ANULLSINK_FILTER)              += asink_anullsink.o
 
 OBJS-$(CONFIG_ASS_FILTER)                    += vf_ass.o
@@ -152,6 +153,7 @@ OBJS-$(CONFIG_SMPTEBARS_FILTER)              += vsrc_testsrc.o
 OBJS-$(CONFIG_TESTSRC_FILTER)                += vsrc_testsrc.o
 
 OBJS-$(CONFIG_BUFFERSINK_FILTER)             += sink_buffer.o
+OBJS-$(CONFIG_FFBUFFERSINK_FILTER)           += sink_buffer.o
 OBJS-$(CONFIG_NULLSINK_FILTER)               += vsink_nullsink.o
 
 OBJS-$(CONFIG_MP_FILTER) += libmpcodecs/mp_image.o