Use the as_flags method instead of map

Library/Homebrew/formula.rb

@@ -453,7 +453,7 @@ class Formula
 
         hsh["installed"] << {
           "version" => keg.version.to_s,
-          "used_options" => tab.used_options.map(&:flag),
+          "used_options" => tab.used_options.as_flags,
           "built_as_bottle" => tab.built_bottle,
           "poured_from_bottle" => tab.poured_from_bottle
         }

Library/Homebrew/tab.rb

@@ -11,8 +11,8 @@ class Tab < OpenStruct
   FILENAME = 'INSTALL_RECEIPT.json'
 
   def self.create(formula, compiler, stdlib, build)
-    Tab.new :used_options => build.used_options.map(&:to_s),
-            :unused_options => build.unused_options.map(&:to_s),
+    Tab.new :used_options => build.used_options.as_flags,
+            :unused_options => build.unused_options.as_flags,
             :tabfile => formula.prefix.join(FILENAME),
             :built_as_bottle => !!ARGV.build_bottle?,
             :poured_from_bottle => false,
@@ -122,8 +122,8 @@ class Tab < OpenStruct
 
   def to_json
     Utils::JSON.dump({
-      :used_options => used_options.map(&:to_s),
-      :unused_options => unused_options.map(&:to_s),
+      :used_options => used_options.as_flags,
+      :unused_options => unused_options.as_flags,
       :built_as_bottle => built_as_bottle,
       :poured_from_bottle => poured_from_bottle,
       :tapped_from => tapped_from,

Library/Homebrew/test/test_tab.rb

@@ -8,8 +8,8 @@ class TabTests < Homebrew::TestCase
     @unused = Options.create(%w(--with-baz --without-qux))
 
     @tab = Tab.new({
-      :used_options       => @used.map(&:to_s),
-      :unused_options     => @unused.map(&:to_s),
+      :used_options       => @used.as_flags,
+      :unused_options     => @unused.as_flags,
       :built_as_bottle    => false,
       :poured_from_bottle => true,
       :tapped_from        => "Homebrew/homebrew",