If you are interested in building for PRS-505, you can use crosstool-4.2 with gcc 2.95. Read
this.
The binary modules will not be compatible with PRS-700 though. For PRS-700 you can use Sourcery G++ Lite EABI (based on gcc 4.3). You can find it
here. I am sure you can find other distros of EABI gcc 4.3 that will work as well.