audit: wrap patches in ENV.with_build_environment block

Library/Homebrew/cmd/audit.rb

@@ -260,8 +260,7 @@ class FormulaAuditor
 
   def audit_patches
     # Some formulae use ENV in patches, so set up an environment
-    ENV.setup_build_environment
-
+    ENV.with_build_environment do
       Patches.new(f.patches).select { |p| p.external? }.each do |p|
         case p.url
         when %r[raw\.github\.com], %r[gist\.github\.com/raw]
@@ -273,6 +272,7 @@ class FormulaAuditor
         end
       end
     end
+  end
 
   def audit_text
     if text =~ /<(Formula|AmazonWebServicesFormula|ScriptFileFormula|GithubGistFormula)/