fix_dynamic_linkage: Check HOMEBREW_RELOCATE_METAVARS
fix_dynamic_linkage: Check HOMEBREW_RELOCATE_METAVARS

Only remove RPATH when HOMEBREW_RELOCATE_METAVARS is set.

See PR https://github.com/Homebrew/brew/pull/5413

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