I know this is a bit of a necro bump but I did release the "cemetech"(as Kerm so happily dubbed it) GCC PrizmSDK-0.2 a while back and would love to help anyone get it setup if needed.
 
As for using it on Mac OS X you would need to install xcode and then compile and install a gcc targetting the superh series processors. If you want I can help walk you through the process any time, just hop on irc, or use the chat box, and highlight me. You would just need some parts of my sdk and I have all those individual files available for download.
 
As to keeping this on par with Simons work I would really love to work with him on standardizing things a bit. I'm fine with the automated syscall generating and have written a script to duplicate its work for use with my SDK but the biggest issues I have are with the header and helper functions organization. As it stands right now you can't easily use the headers from one SDK with another or even reliably compile code written with one on another.
 
I'd like to fix that so that it is easier for the end users of either SDK to adapt them to their needs.
 
My first issue is the lack of clarity on whether or not C++ is really supported and why some headers and source files use hpp/cpp instead of h/c. IMO we should keep the SDK's and their API's pure C and leave it up to the users as to whether they want to use C or C++. Many of your headers are already encased in Extern "C" {} so why even bother having them use the .hpp extension?
 
My second issue also relates to the headers and it is the fact that you mix equates and structs used by syscalls with custom functions you have added. This increase the amount of work for me greatly and adds to user confusion because they can't tell what is a syscall and what is something you added to the SDK yourself.
 
My last issue is that darn chm file. Yes its nice that there is some documentation but damn is it a pain in the arse to find any of it in there. Omnimaga was kind enough to host the prizmwiki at http://prizmwiki.omnimaga.org we should use it. I have been trying to update it with some of the things I have found but its just not all that useful as it currently stands. I think the first step would be to start getting the syscalls on there. The documentation for them is scattered about this forum, your .chm file and our heads. Getting on in a centralized location would help everyone move forward and allow one to much easier find the information they need.

Making separate wiki articles for the syscalls will make it much easier to find information. I'll create the category, links to it and such right now, but I'll need some help with adding information about the syscalls since there are so many of them.

EDIT: I've added a few syscalls, and they can be accessed by hexadecimal number from [prizm]Category:Prizm syscalls[/prizm]. Maybe there should also be categories that are based on what syscalls are used for (displaying things, file management, etc.) or lists with names of syscalls?

I was planning to do it like on WikiTI, in which the article names use numbers and the lists use names. I haven't figured out how to use names within the automatically generated lists, though.

We also need to modify the header files from both SDK's to have proper #ifndef blah_h, #define blah_h, #endif statements so that other libraries don't end up being accidently included twice once more third party libraries become available. 

What I think would be really cool is if we could somehow make it so the syscall and general routine library could be portable between the compilers. For syscalls the asm.h header just needs to use the proper macro for the platform, along with the asm source files but the C sources should easily be portable between them with a little clean up.

I already have libfxcg hosted on github so that is a start but many of simon's helper routines don't even compile with gcc due to header file case errors, syntax differences and a few other issues.

I have the same problem... I don't know how can I build some g3a.

I made a french tutorial to use mini-SDK, inspired by the Cemetech's...

http://www.planet-casio.com/Fr/forums/topic10062-1-[C]-Du-C-sur-la-Prizm-Du-monochrome-a-la-couleur.html
Enjoy!