Merge pull request #3358 from maxim-belkin/build-env2

build_environment: add Linux-specific environment variables

Library/Homebrew/build_environment.rb

@@ -46,6 +46,7 @@ module Homebrew
       HOMEBREW_SDKROOT HOMEBREW_BUILD_FROM_SOURCE
       MAKE GIT CPP
       ACLOCAL_PATH PATH CPATH
+      LD_LIBRARY_PATH LD_RUN_PATH LD_PRELOAD LIBRARY_PATH
     ].select { |key| env.key?(key) }
   end