Sort the enums in a stable manner

Order of enums generated by function `output_tokens` is unstable

I found this commit (https://github.com/nigels-com/glew/commit/3739be33b026df7de070fc08ed48366b6dafa236) changes `auto/bin/make.pl` and `auto/bin/parse_spec.pl`
but other commit (https://github.com/nigels-com/glew/commit/d04fd20cecd015ec2bfdf44230aef5151dc60248) changes only `auto/bin/parse_spec.pl`

I applied same compare logic to `output_tokens`