Install plists by default

Library/Homebrew/build.rb

@@ -141,6 +141,16 @@ def install f
     else
       f.prefix.mkpath
       f.install
+
+      # Install a plist if one is defined
+      unless f.startup_plist.nil?
+        unless f.plist_path.exist?
+          f.plist_path.write f.startup_plist
+          f.plist_path.chmod 0644
+        end
+      end
+
+      # Find and link metafiles
       FORMULA_META_FILES.each do |filename|
         next if File.directory? filename
         target_file = filename

Library/Homebrew/formula.rb

@@ -140,6 +140,8 @@ class Formula
   # generally we don't want var stuff inside the keg
   def var; HOMEBREW_PREFIX+'var' end
 
+  # override this to provide a plist
+  def startup_plist; nil; end
   # plist name, i.e. the name of the launchd service
   def plist_name; 'homebrew.mxcl.'+name end
   def plist_path; prefix+(plist_name+'.plist') end