Cross compiling PHP

I am interested in updating the PHP package for OpenWrt, a Linux distribution for routers and other similar devices. Due to the wide variety of devices supported, packagers generally cross compile OpenWrt packages. It seems that PHP 5.6.4 is a little more difficult to cross compile than OpenWrt's last supported version, 5.4.36. For example, 5.6.4's "./configure ..." prints an error which states that the test program responsible for checking for the existence of strcasestr cannot run. (The reason it cannot run is that it was not compiled for the host architecture.) Has anyone successfully cross compiled PHP 5.6.4? Does a document exist which describes how to cross compile the newer versions of PHP? Is anyone interested in helping to modify the PHP build system to make it more cross-compile friendly? Thank you, -- Mike :wq