Gemfile: add :x64_mingw platform missing in r13651

git-svn-id: http://svn.redmine.org/redmine/trunk@13654 e93f8b46-1217-0410-a6f0-8f06a7374b81

Gemfile

 gem "actionpack-action_caching"
 
 # Windows does not include zoneinfo files, so bundle the tzinfo-data gem
-gem 'tzinfo-data', platforms: [:mingw, :mswin, :jruby]
+gem 'tzinfo-data', platforms: [:mingw, :x64_mingw, :mswin, :jruby]
 gem "rbpdf", "~> 1.18.2"
 
 # Optional gem for LDAP authentication
   gem "rack-openid"
 end
 
-platforms :mri, :mingw do
+platforms :mri, :mingw, :x64_mingw do
   # Optional gem for exporting the gantt to a PNG file, not supported with jruby
   group :rmagick do
     gem "rmagick", ">= 2.0.0"