I'm not able to build any module for Apache on windows.
Can you provide a build for mod_proxy_handler?
Seems much easier to use PHP-FPM with it.
Source can be found here:
https://gist.github.com/progandy/6ed4eeea60f6277c3e39
I'll look at it tonight. I might even build a patched mod_proxy for testing since this module states it is a temporary workaround.
I built VC9 modules last night, they will work in our VC11 2.4 builds as well (provided you also have the VC9 redistributable installed).
https://www.apachehaus.net/modules/untested/