This one is still valid for libopencv-dev 4.2.0+dfsg-5 in focal! Now with multiarch path but still:
/usr/lib/x86_64-linux-gnu/pkgconfig/opencv4.pc: includedir_old=${prefix}/include/opencv4/opencv includedir_new=${prefix}/include/opencv4
But there is only /usr/include/opencv4/opencv2 as an include folder
This one is still valid for libopencv-dev 4.2.0+dfsg-5 in focal! Now with multiarch path but still:
/usr/lib/ x86_64- linux-gnu/ pkgconfig/ opencv4. pc: old=${prefix} /include/ opencv4/ opencv new=${prefix} /include/ opencv4
includedir_
includedir_
But there is only opencv4/ opencv2
/usr/include/
as an include folder