extend/ARGV: don't warn on --build-arch=.
extend/ARGV: don't warn on --build-arch=.

Fixes #5504.

mahori/brew,nandub/brew,claui/brew,JCount/brew,konqui/brew,Linuxbrew/brew,nandub/brew,sjackman/homebrew,Linuxbrew/brew,Homebrew/brew,claui/brew,mahori/brew,vitorgalvao/brew,reitermarkus/brew,Linuxbrew/brew,reitermarkus/brew,mahori/brew,claui/brew,MikeMcQuaid/brew,EricFromCanada/brew,vitorgalvao/brew,JCount/brew,sjackman/homebrew,vitorgalvao/brew,konqui/brew,konqui/brew,Homebrew/brew,MikeMcQuaid/brew,vitorgalvao/brew,konqui/brew,EricFromCanada/brew,sjackman/homebrew,nandub/brew,nandub/brew,Homebrew/brew,EricFromCanada/brew,mahori/brew,claui/brew,EricFromCanada/brew,Homebrew/brew,JCount/brew,MikeMcQuaid/brew,JCount/brew,reitermarkus/brew,MikeMcQuaid/brew,Linuxbrew/brew,reitermarkus/brew,sjackman/homebrew