avcodec/Makefile: add missing dep for g723_1 encoder

Signed-off-by: James Almer <jamrial@gmail.com>

libavcodec/Makefile

@@ -281,7 +281,7 @@ OBJS-$(CONFIG_G2M_DECODER)             += g2meet.o elsdec.o
 OBJS-$(CONFIG_G723_1_DECODER)          += g723_1dec.o g723_1.o \
                                           acelp_vectors.o celp_filters.o celp_math.o
 OBJS-$(CONFIG_G723_1_ENCODER)          += g723_1enc.o g723_1.o \
-                                          acelp_vectors.o celp_filters.o
+                                          acelp_vectors.o celp_filters.o celp_math.o
 OBJS-$(CONFIG_G729_DECODER)            += g729dec.o lsp.o celp_math.o acelp_filters.o acelp_pitch_delay.o acelp_vectors.o g729postfilter.o
 OBJS-$(CONFIG_GIF_DECODER)             += gifdec.o lzw.o
 OBJS-$(CONFIG_GIF_ENCODER)             += gif.o lzwenc.o