os/mac: remove sdk_version
os/mac: remove sdk_version

MikeMcQuaid/brew,sjackman/homebrew,claui/brew,JCount/brew,EricFromCanada/brew,vitorgalvao/brew,nandub/brew,JCount/brew,claui/brew,nandub/brew,MikeMcQuaid/brew,EricFromCanada/brew,claui/brew,Homebrew/brew,sjackman/homebrew,nandub/brew,MikeMcQuaid/brew,Homebrew/brew,nandub/brew,vitorgalvao/brew,JCount/brew,sjackman/homebrew,EricFromCanada/brew,MikeMcQuaid/brew,EricFromCanada/brew,vitorgalvao/brew,JCount/brew,Homebrew/brew,claui/brew,Homebrew/brew,sjackman/homebrew,vitorgalvao/brew