cc: filter more flags clang hates.
cc: filter more flags clang hates.

Should help with the Xcode 5.1 madness.

Closes Homebrew/homebrew#27549.

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