[FFmpeg-user] ffmpeg 4.0.2 and above missing 'ffio_open_dyn_packet_buf' from avformat.lib & avformat.dll

[Dinesh Gupta]

While building 'ffmpeg' 4.0.2 and above, missing function
'ffio_open_dyn_packet_buf'. Due to this I am unable to compile my project.
I spend my whole week to find the solution but didn't get success. When
searching this function in code than it is available on source code.But
when build from sorce code this function is missing. Please guide me what I
need to do.

./libavformat/aviobuf.c:1396:int ffio_open_dyn_packet_buf(AVIOContext
*s, int max_packet_size)./libavformat/avio_internal.h:120:int
ffio_open_dyn_packet_buf(AVIOContext *s, int max_packet_size);
./libavformat/movenchint.c:430: if ((ret =
ffio_open_dyn_packet_buf(&rtp_ctx->pb,
./libavformat/rtpenc_chain.c:85: ret =
ffio_open_dyn_packet_buf(&rtpctx->pb, packet_size);
./libavformat/rtspenc.c:158: * ffio_open_dyn_packet_buf. So by writing the
interleaving header
./libavformat/rtspenc.c:178: return ffio_open_dyn_packet_buf(&rtpctx->pb,
RTSP_TCP_MAX_PACKET_SIZE);

I have below environment:
OS : Windows 10
MSVC : Visual Studio 15 with Windows SDK 10.0.17763.0
MSYS2 : MINGW32_NT-10.0-WOW

Getting below error:

server-ffmpeg.obj : error LNK2019: unresolved external symbol
_ffio_open_dyn_packet_buf referenced in function "int cdecl
ff_server_send_packet_1(char const *,void *,int,struct AVPacket *,int64,struct
timeval *)" (?ff_server_send_packet_1@@YAHPBDPAXHPAUAVPacket@@_JPAUtimeval@
@@Z)

rtspserver.obj : error LNK2019: unresolved external symbol
_ff_rtsp_parse_line referenced in function "void * cdecl rtspserver(void
*)" (?rtspserver@@YAPAXPAX at Z)
server-ffmpeg.dll : fatal error LNK1120: 1 unresolved externals

Please guild me to achieve above result.

Thanks