Don't Do That! this is not XAMPP's mission.
From the Philosphy section of the website
The philosophy behind XAMPP is to build an easy to install distribution for developers to get into the world of Apache. To make it convenient for developers XAMPP is configured with all features turned on.
The default configuration is not good from a securtiy point of view and it's not secure enough for a production environment - please don't use XAMPP in such environment.
Note that it says for developers... and not secure enough for production websites so don't try and make it do something it's not designed for.
Sure, people will use it in production, people will use pretty much torture anything into production but that doesn't make it right.
Use the correct tools for the job, XAMPP for development and a suitably tuned web stack for production.
Further reading:
Can you help me with my capacity planning?
How do you do load testing and capacity planning for web sites?