Using cmake for Microware os9 Compiler xcc(cross-compile) and g++(Linux)

I am trying to use cmake to use the toolchain from Microware. The only post i found about this is:

but this did not help me.
The xcc compiler generates .ii and .r files and the libgen links those to a .l file.
As I have a project with 15 modules do not want to fiddle with every single module but would like to have the edit each individual cmake-file but would like to have the definitions in a central cmake-file.
Getting cmake to build makefiles to compile the cpp into .r/.ii was quite easy as i only had to specify the CMAKE_C_COMPILER with the correct parameters. But I am not able to link the files as the cmake-command add_library always considers the input-files for the linker beeing .o files.
Is there a good way of getting cmake to use this xcc/libgen toolchain ?

Best regards;
Martin