@paolone
Very good to know as far as metamake. Following your very good example I can now put together a few metamake files including the one for the bmp datatype you asked for earlier.
Is this method also used to compile Magellan and Multiview and other modules for 64 bit?
I'm happy my example helped you understanding how the logic of metamake works. However, I suggest you to take some time and look for other mmakefile.src files included with AROS sources (in my development VM, just look for them in ~/sources), you will notice that they can be very different from each others. Some will be very simple, basic ones like mine, but others can be very, very complex, exacly like it happens with common 'makefile'.
We surely have a mmakefile.src for MultiView, since it's part of AROS programs. But unluckily we haven't anything similar for Magellan, which is not available for 64bit AROS.
The problem with bigger, 3rd party programs, is that they might use different tools to compile, they might have their own toolchain and we simply can't force everyone to use metamake files as we'd wish. Everyone must be free to use whatever they like. Unluckily, this also means that they will have to keep their AROS headers and files as much updated as possible, because otherwise their binaries wouldn't run on current system.
Just to be clear: except the ones I personally released, NO OTHER x86-64 PROGRAM ever released on The Archives is working on Icaros 64. Neither various MCC zune libraries, nor MuiMapparium or the recent Leu, nor fpc. That's simply because the ABI slightly changed between the time their authors compiled the binaries, and today. AND they are also using a older x86-64 AROS base to compile. This 'moving target' nature of AROS 64 is the main motivation why I waited for so much, before even trying to make a 64bit distribution. And I simply CAN'T ask several people to rebuild their programs every time AROS changes. If they used metamake files, however, thir effort would be little: just updating AROS sources and rebuild would be enough.