_XOPEN_SOURCE      23 ffmpeg.c       #define _XOPEN_SOURCE 600
_XOPEN_SOURCE      22 ffserver.c     #define _XOPEN_SOURCE 600
_XOPEN_SOURCE      29 libavcodec/utils.c #define _XOPEN_SOURCE 600
_XOPEN_SOURCE      23 libavformat/rtpdec.c #define _XOPEN_SOURCE 600