The GoPHP7 project has posted their initiative to try to improve the world of PHP for extensions and make them "first class citizens of the PHP community".
The goals of gophp7(ext) [are to]: get PHP extensions running "out of the box" when PHP7 is released (no lag time), make extensions in general easier to install and use (binaries, ppas), get more people involved in extension maintenance (and travis/appveyor running on them all, killing off bugs), get more documentation written for extension writing and codify some of the "best practices" of extension writing and design (a la PSR).
They're asking for help from anyone interested, even if you don't know C (what PHP extensions are written in). The project asks for just 30 minutes a day to help achieve their goals. The page also lists out the different ways you can help including cataloging the work that needs to be done on the catalog page and working on the development systems for PHP7 to make working with the extensions easier.