GLintptr and GLsizeiptr not defined
I generate a loader with the following command line:

```
glad --api gles2=2.0 --profile core --generator c --spec gl --out-path out --no-loader
```

But I can not compile the resulting file because `GLintptr` and `GLsizeiptr` are not defined. This bug appeared between version 0.1.13a and 0.1.14a. I think it may be related to the change of registry in commit 2e24db13434d2a802d8126549880f434e618a7bb.

I have the same bug with `--api gl=3.3`.
