fix VC 2013 compile error
It seems the compiler does not support VLAs. See also: https://ci.appveyor.com/project/ruby/ruby/builds/26392589/job/px6nuiuw4e78weg1
fix VC 2013 compile error
It seems the compiler does not support VLAs.
See also: https://ci.appveyor.com/project/ruby/ruby/builds/26392589/job/px6nuiuw4e78weg1