Add --with-debug option when building Nginx package
The `—with-debug` option is not provided to `./configure` when building Nginx, as shown here:
https://git.alpinelinux.org/cgit/aports/tree/main/nginx/APKBUILD
This prevents usage of the `debug` severity to `error_log`, as per [this documentation](http://nginx.org/en/docs/debugging\_log.html).
Please add `—with-debug` to the list of configuration parameters so that nginx may use the `debug` severity.
(from redmine: issue id 9594, created on 2018-10-28)