To build a Linux library, use a more modern version than you will get by default on Rocky Linux 8. You should obtain and build a toolchain before. Script what can do it you can find in Engine/Build/BatchFiles/Linux/SetupToolchain.sh. You can set up the environment by running script Engine/Build/BatchFiles/Linux/Setup.sh. An easier way to build is to use script build-libvpx-linux.sh in a dedicated Linux machine. if you want use Epic toolchain, you can set UE_ROOT_DIR environment variablr to path with toolchain or build the library in thr docker container. If you want to build in docker, you need get Epic toolchain and use build-libvpx-for-linux-in-docker.sh script Minimum requered folders to build: /* - Root files /Engine/Build /Engine/Source/ThirdParty/LibCxx Need install Linux toolchain by run script "Engine/Build/BatchFiles/Linux/SetupToolchain.sh" from shell (Git Bash, etc.) It will install toolchain /Engine/Extras/ThirdPartyNotUE/SDKs/HostLinux/Linux_x64/ Script build-libvpx-for-linux-in-docker.sh and file rockylinux8_build_libvpx.dockerfile can be used to build the library using Epic toolchain. Use comamnd line option -t fot it. Another options can see by run the script with -h option.