With this you can now support more connections on linux, even if your system header is still set to a smaller value.
Make sure to increase the limit of open file handles with ulimit or other resource related settings.
You can change the compile time value of supported connections with ./configure --with-maxconn=value
Windows default is still 4096.
Fixes#3017
Thanks to Hercules for the idea and their implementation of it.
This deprecates Windows XP support. If you want to use it to run your server on it, you have to forcefully enable it now.
Since 64bit ticks do not exist on XP, you might encounter some issues that are already fixed on other OS.
* Alphabetically sorted includes.
* Updated copyright and license text to match across all files.
* Removed pragma once define in header files in lieu of ifdef guards.
