Build opus codec for iOS
Run ./sync.sh, ./build.sh and ./combine.sh as appropriate. It is probably needed to change some variables in ./config.sh.
To find out which SDKs are supported run: xcodebuild -showsdks
To switch which XCode Installation is used, run sudo xcode-select -switch $XCODEROOT
Part of code is based on https://github.com/zimuliu/ffmpeg-ios-build