If your company is affected by lack of XP support in this PHP build, it should be a temporary convenience at worst. What are your plans to migrate off XP over the next year? As of next April there will be no patches or security fixes coming for XP. Is your company planning on paying Microsoft for continued support, or will it negotiate extended XP support in return for buying company-wide Windows 8 licenses and start the ride over again?
I suspect that many of the people using XP today are frozen and wouldn't upgrade their PHP anyway, for the same reasons they're using XP and IE6. They either don't want to change their software because of cost/risk issues or the people who wrote it moved on years ago and they have no idea how it works.
There's not been any security patches for PHP 4 for many years, but people still use it. Those same sorts of orgs will continue to use stuff out of date and unsupported for any number of reasons. Catering development processes around an increasingly small number of users doesn't make sense.
Since I've moved to the camp of "You developing PHP and use Windows? Let me show you how to setup Vagrant" I've become less concerned about the state of PHP & Windows. I just won't tolerate when people say PHP dropping XP support is a good thing (which the OP wasn't saying, but some have.)
1. http://lxr.php.net/search?q=&defs=&refs=NETWARE&...