Don't call methods on xcrun_path if it's nil
Don't call methods on xcrun_path if it's nil

mistydemeo/homebrew,konqui/brew,MikeMcQuaid/brew,EricFromCanada/brew,bfontaine/brew,nandub/brew,Linuxbrew/brew,aw1621107/brew,amar-laksh/brew_sudo,hanxue/linuxbrew,gordonmcshane/homebrew,Linuxbrew/brew,JCount/brew,EricFromCanada/brew,hanxue/linuxbrew,pseudocody/brew,claui/brew,maxim-belkin/brew,vitorgalvao/brew,claui/brew,ilovezfs/brew,staticfloat/brew,palxex/brew,AnastasiaSulyagina/brew,alyssais/brew,toonetown/homebrew,bfontaine/brew,DomT4/brew,JCount/brew,AnastasiaSulyagina/brew,maxim-belkin/brew,mahori/brew,toonetown/homebrew,Linuxbrew/brew,konqui/brew,muellermartin/dist,vitorgalvao/brew,mgrimes/brew,amar-laksh/brew_sudo,Homebrew/brew,toonetown/homebrew,rwhogg/brew,gordonmcshane/homebrew,gordonmcshane/homebrew,gregory-nisbet/brew,tonyg/homebrew,MikeMcQuaid/brew,tonyg/homebrew,rwhogg/brew,aw1621107/brew,jmsundar/brew,vitorgalvao/brew,mahori/brew,mgrimes/brew,zmwangx/brew,MikeMcQuaid/brew,bfontaine/brew,maxim-belkin/brew,sjackman/homebrew,zmwangx/brew,hanxue/linuxbrew,vitorgalvao/brew,claui/brew,reitermarkus/brew,palxex/brew,JCount/brew,palxex/brew,mahori/brew,reelsense/brew,alyssais/brew,zmwangx/brew,muellermartin/dist,reitermarkus/brew,ilovezfs/brew,DomT4/brew,konqui/brew,MikeMcQuaid/brew,DomT4/brew,rwhogg/brew,EricFromCanada/brew,sjackman/homebrew,Homebrew/brew,jmsundar/brew,muellermartin/dist,reelsense/brew,gregory-nisbet/brew,jmsundar/brew,gregory-nisbet/brew,reitermarkus/brew,staticfloat/brew,aw1621107/brew,DomT4/brew,sjackman/homebrew,mahori/brew,Homebrew/brew,nandub/brew,mistydemeo/homebrew,Linuxbrew/brew,mgrimes/brew,konqui/brew,claui/brew,reelsense/brew,nandub/brew,staticfloat/brew,mistydemeo/homebrew,pseudocody/brew,AnastasiaSulyagina/brew,sjackman/homebrew,Homebrew/brew,reitermarkus/brew,nandub/brew,pseudocody/brew,alyssais/brew,EricFromCanada/brew,amar-laksh/brew_sudo,ilovezfs/brew,tonyg/homebrew,JCount/brew