I recently ran into an issue with this because building an iOS .ipa from the command line with xcodebuild apparently ends up shelling out to call rsync to copy some files between local directories, and because I had homebrew rsync earlier in $PATH, it would end up running homebrew rsync, but xcodebuild passed an openrsync-only command line argument "--extended-attributes" that homebrew rsync doesn't understand and would exit with a failure.