OK I've found very easy way to edit Gecko to get the build to complete. The complete patch is as follows:

http://paste2.org/p/2464566

Copy the above to a new file in the gecko folder called armv6.patch and then run git am armv6.patch to apply it. No more hacking out the armv7 code!

I've also got a new manifest.xml, it's mostly codeaurora stuff in stead of cyanogenmod stuff:

http://paste2.org/p/2464574

The build folder needs this patch:

http://paste2.org/p/2464583

You need to add this gps.h to your device folder, in the include/hardware folder. This location for P500, yours will be different.

Lastly there is a small change to external/webrtc/src/common_audio/signal_processing_library/main/interface/spl_inl.h At the top of the file is __ARM_ARCH_5__ twice. These need to be changed to __ARM_ARCH_6__

I haven't tested the build yet, but it finished. Clean your B2G folder and give it a try!