@tty@todrobbins yep what Kira said! I'm working on a project that uses redbean (their portable webserver implementation) and I'm able to work on it on my MacBook, stick the executable on a thumb drive, and then run it on a Linux laptop! (while still in the thumbrive, if you so choose)
usually you would have to make sure that your system has the tools the program needs and ensure that they're built for the system before you could run the program. cosmopolitan sidesteps all of that!