The opencv-dev package from here:
https://repo.download.nvidia.com/jetson/common/pool/main/libo/libopencv-dev/libopencv-dev_4.8.0-1-g6371ee1_arm64.deb
contains an incorrectly configured opencv4.pc file:
# Package Information for pkg-config
prefix=/usr/local
exec_prefix=${prefix}
libdir=${exec_prefix}/lib
includedir=${prefix}/include/opencv4
Name: OpenCV
Description: Open Source Computer Vision Library
Version: 4.8.0
Libs: -L${exec_prefix}/lib -lopencv_gapi -lopencv_highgui -lopencv_ml -lopencv_objdetect -lopencv_photo -lopencv_stitching -lopencv_video -lopencv_calib3d -lopencv_features2d -lopencv_dnn -lopencv_flann -lopencv_videoio -lopencv_imgcodecs -lopencv_imgproc -lopencv_core
Libs.private: -ldl -lm -lpthread -lrt
Cflags: -I${includedir}
The prefix=/usr/local is incorrect - the actual installed path is /usr
When compiling gstreamer with meson it uses the package config files to set the include and library paths for the build. With the incorrect file above these paths are wrong and the build fails. A temp fix is to edit the config file before the build but this needs correcting for future updates