audit: only set up the build environment once

Library/Homebrew/cmd/audit.rb

@@ -7,6 +7,8 @@ module Homebrew extend self
     formula_count = 0
     problem_count = 0
 
+    ENV.setup_build_environment
+
     ff = if ARGV.named.empty?
       Formula
     else
@@ -295,9 +297,7 @@ class FormulaAuditor
   end
 
   def audit_patches
-    # Some formulae use ENV in patches, so set up an environment
-    ENV.with_build_environment do
-      Patches.new(f.patches).select { |p| p.external? }.each do |p|
+    Patches.new(f.patches).select(&:external?).each do |p|
       case p.url
       when %r[raw\.github\.com], %r[gist\.github\.com/raw]
         unless p.url =~ /[a-fA-F0-9]{40}/
@@ -308,7 +308,6 @@ class FormulaAuditor
       end
     end
   end
-  end
 
   def audit_text
     if text =~ /<(Formula|AmazonWebServicesFormula|ScriptFileFormula|GithubGistFormula)/