[CMake] adding extra resources to MACOSX package

[Benoit Callebaut]

Hello,
How can I copy external resources in the MACOSX bundle.
I haven't seen any command to do this.

I also need to change paths in a config file depending on the  
packaging (MACOSX or Linux or Windows).
Is it possible to call some external program like sed ,awk or a custom  
script in CMAKE ?

My target is a makefile but a solution also valid for XCode and  
Code::Blocks would also be great.

Thanks