mencoder build failure

[Mike Pumford <mpumford%mudcovered.org.uk@localhost>]

Building on 10.0RC3 amd64 in a chroot environment:

ffmpeg5 -I/usr/pkg/include/ffmpeg5 -I/usr/pkg/include -c -o libaf/af.o 
libaf/af.c
codec-cfg.c:60:10: fatal error: libavutil/avutil.h: No such file or 
directory
   60 | #include "libavutil/avutil.h"
      |          ^~~~~~~~~~~~~~~~~~~~
compilation terminated.
gmake: *** [Makefile:756: codec-cfg] Error 1
gmake: *** Waiting for unfinished jobs....
*** Error code 2


This has been failing for a couple of weeks now. My last successful 
build was on 24th Jan if that helps narrow things down.

The chroot is created completely fresh for each package set build so all 
packages built are consistently built from the same pkgsrc revision.

Mike