Ye, if you felt like working on this some more for integration, what I'd like to see is all the current build options and features preserved for the GCC build.
I think the best way to go would be to create 3 makefiles -- one main Makefile for all the common options and build steps/targets, and then one each specifically for CW and GCC builds which get included in the main one as needed. The latter should only do things which are compiler-specific. The build type (CW/GCC) could perhaps be specified on the Make command-line (with default being CW for now).
A lot of the current build system options/features are used for automated builds and across multiple project files, so they need to stay and be centrally editable (not needing to modify stuff in two places). Being able to include user-defined settings from an external makefile is essential. Auto-incrementing the build number and labeling the bin files with the right version are important, and things like the elf size report are invaluable during development.
Anyway, those would be my next steps once I got time. If you're up for doing some/all of it, that would be great. I'm open to other ideas as well, but the end result must require the least amount of maintenance possible...
Thanks,
-Max