[thamer]

There are a number of blog posts online and StackOverflow questions explaining IOCCC entries, and they generally seem to be built/obfuscated by hand. It's an art and it's far from trivial, which is one of the reasons why the contest exists :)

For an example, see this StackOverflow question and its detailed answers for an overview of what obfuscation techniques can be used, although many more exist of course: https://stackoverflow.com/questions/15393441/obfuscated-c-co...

I was able to compile it on macOS, but had to include an extra flag to stop clang from being too strict (version 16):

    cc -Wno-implicit-function-declaration -std=c89 -o test test.c
    ./test