Pin ffi on Ruby 2.3 on Windows

Author: JonRowe

Gemfile

@@ -47,6 +47,8 @@ end
 
 if RUBY_VERSION < '2.2.0' && !!(RbConfig::CONFIG['host_os'] =~ /cygwin|mswin|mingw|bccwin|wince|emx/)
   gem 'ffi', '< 1.10'
+elsif RUBY_VERSION < '2.4.0' && !!(RbConfig::CONFIG['host_os'] =~ /cygwin|mswin|mingw|bccwin|wince|emx/)
+  gem 'ffi', '< 1.15'
 elsif RUBY_VERSION < '2.0'
   gem 'ffi', '< 1.9.19' # ffi dropped Ruby 1.8 support in 1.9.19
 elsif RUBY_VERSION < '2.3.0'