[MPlayer-users] make: error: 'CONFIG_MSMPEG4DEC' undeclared

[max muster]

Hello,i've got the following error if i compile mplayer from actual SVN and actual FFMPEG git in MSYS2 environment:
$ make
make -C ffmpeg libavcodec/libavcodec.a
make[1]: Entering directory '/trunk/mplayer-unpatched/ffmpeg'

WARNING: libavdevice/alldevices.c libavfilter/allfilters.c libavformat/allformats.c libavcodec/allcodecs.c libavcodec/bitstream_filters.c libavcodec/hwaccels.h libavcodec/parsers.c libavformat/protocols.c newer than config_components.h, rerun configure

CC      libavcodec/h263dec.o
In file included from libavcodec/h263dec.c:42:
libavcodec/internal.h:36:5: warning: "CONFIG_LCMS2" is not defined, evaluates to 0 [-Wundef]
   36 | #if CONFIG_LCMS2
      |     ^~~~~~~~~~~~
libavcodec/internal.h:162:5: warning: "CONFIG_LCMS2" is not defined, evaluates to 0 [-Wundef]
  162 | #if CONFIG_LCMS2
      |     ^~~~~~~~~~~~
libavcodec/h263dec.c: In function 'ff_h263_decode_frame':
libavcodec/h263dec.c:505:16: error: 'CONFIG_MSMPEG4DEC' undeclared (first use in this function); did you mean 'CONFIG_MPEG_ER'?
  505 |     } else if (CONFIG_MSMPEG4DEC && s->msmpeg4_version) {
      |                ^~~~~~~~~~~~~~~~~
      |                CONFIG_MPEG_ER
libavcodec/h263dec.c:505:16: note: each undeclared identifier is reported only once for each function it appears in
make[1]: *** [ffbuild/common.mak:81: libavcodec/h263dec.o] Error 1
make[1]: Leaving directory '/trunk/mplayer-unpatched/ffmpeg'
make: *** [Makefile:744: ffmpeg/libavcodec/libavcodec.a] Error 2

Is it a known issue ?
Regards, Mark