Set "siteurl" to "localhost:5000" in testserver

I chose to output settings.ini's siteurl property in order to make it easier to construct urls in JavaScript in https://gitlab.com/eyeo/websites/web.adblockplus.org/merge_requests/11/diffs?commit_id=dfc7e9fbfa07287c6360959c45812d51d90d70e7. But this doesn't work on localhost (using the testing server) unless one sets their siteurl to localhost:5000 (or similar). Can you:

1. Set siteurl to the host and port of the testing server when using the testing server
2. Think of a better solution?

The original problem was that adblockplus.org was not programmed to be accessible via subirectory e.g. http://juliandoucette.gitlab.io/abp-new-index/en/ (as a result, several CMS, CSS, and JavaScript features didn't work until I corrected for them in https://gitlab.com/eyeo/websites/web.adblockplus.org/merge_requests/11/diffs?commit_id=51287f6ebc1e6439a87d4f176bc943b77767f9d9.