The MP2/MP3 muxer uses ff_id3v2_tags, so add the correct object dependency.

Originally committed as revision 20326 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/Makefile

@@ -106,9 +106,9 @@ OBJS-$(CONFIG_MMF_DEMUXER)               += mmf.o raw.o
 OBJS-$(CONFIG_MMF_MUXER)                 += mmf.o riff.o
 OBJS-$(CONFIG_MOV_DEMUXER)               += mov.o riff.o isom.o
 OBJS-$(CONFIG_MOV_MUXER)                 += movenc.o riff.o isom.o avc.o
-OBJS-$(CONFIG_MP2_MUXER)                 += mp3.o id3v1.o
+OBJS-$(CONFIG_MP2_MUXER)                 += mp3.o id3v1.o id3v2.o
 OBJS-$(CONFIG_MP3_DEMUXER)               += mp3.o id3v1.o id3v2.o
-OBJS-$(CONFIG_MP3_MUXER)                 += mp3.o id3v1.o
+OBJS-$(CONFIG_MP3_MUXER)                 += mp3.o id3v1.o id3v2.o
 OBJS-$(CONFIG_MPC_DEMUXER)               += mpc.o id3v1.o id3v2.o apetag.o
 OBJS-$(CONFIG_MPC8_DEMUXER)              += mpc8.o
 OBJS-$(CONFIG_MPEG1SYSTEM_MUXER)         += mpegenc.o