Coerce flags to an array in `remove_make_var!`
Coerce flags to an array in `remove_make_var!`

This is needed for Ruby 1.9.x compatibility, but we still don't support
running Homebrew with anything other than a system provided 1.8.[67].

Fixes Homebrew/homebrew#6546

Signed-off-by: Adam Vandenberg <34c2b6407fd5a10249a15d699d40f9ed1782e98c@gmail.com>

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