Merge pull request #4185 from sjackman/superenv-linux

Library/Homebrew/build.rb

Library/Homebrew/extend/ENV/super.rb

Library/Homebrew/extend/os/extend/ENV/super.rb

Library/Homebrew/extend/os/linux/extend/ENV/super.rb

Library/Homebrew/extend/os/mac/extend/ENV/super.rb

Library/Homebrew/shims/linux/super/c++

Library/Homebrew/shims/linux/super/c89

Library/Homebrew/shims/linux/super/c99

Library/Homebrew/shims/linux/super/cc

Library/Homebrew/shims/linux/super/clang

Library/Homebrew/shims/linux/super/clang++

Library/Homebrew/shims/linux/super/cpp

Library/Homebrew/shims/linux/super/g++

Library/Homebrew/shims/linux/super/g++-4.2

Library/Homebrew/shims/linux/super/g++-4.3

Library/Homebrew/shims/linux/super/g++-4.4

Library/Homebrew/shims/linux/super/g++-4.5

Library/Homebrew/shims/linux/super/g++-4.6

Library/Homebrew/shims/linux/super/g++-4.7

Library/Homebrew/shims/linux/super/g++-4.8