I am trying to use XTC68 (and not QDOS-GCC as I wrote initially).
I have managed to build the version at: https://github.com/stronnag/xtc68
This version has no crt.o, no headers and no libs and no instructions on how to install them other than a link to http://www.dilwyn.me.uk/c/index.html
No instructions on how to use the compiler, either

In the linked pages I can find crt.o and the libs. I have managed to manually put them at the right locations and rename them to their expected names.
The repository has a Perl script that maybe does the installation of libs and headers but I am not able to understand how to use it.
Anyway, I have managed to compile a "Hello World" example.
Now the most serious problem for me is to figure out how to run the obtained binaries:
- Do I need to convert these binaries to some specific tape/disk images? With which tools?
- Which emulator(s) should I use and how do I load and run the binary?
Fabrizio
P.S.: The ultimate goal is to make a QL version of my universal retro-game (https://github.com/Fabrizio-Caruso/CROSS-CHASE)