Mandatory version headers totally ruin your "hello, world!" comparison chart story ;-)
Once, when the C standards committee was struggling with the semantics of "main" under Windows, I suggested that "main" not be part of the language at all. You would include <unix.h> or <posix.h> or <dos.h>, and get "int main(int argc; char *argv[]);" as a prototype, which you must define. Or you include <windows.h>, and "int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow);" is the function you must write. The runtime pulled in would call the appropriate function. "main" would no longer be a special case. This was generally agreed to be the correct solution, but too upsetting for beginners.
It'd be unfortunate to have to include a platform-specific header in otherwise portable code. Why have to include a <posix.h> versus <dos.h> if they both define main the same way? (Windows aside.)
You can use vanilla `main` for Windows apps too, just need to override the default subsystem when invoking the linker. I never understood the point of `WinMain`; IIRC there's nothing it does that you can't do just as well without it.
Once, when the C standards committee was struggling with the semantics of "main" under Windows, I suggested that "main" not be part of the language at all. You would include <unix.h> or <posix.h> or <dos.h>, and get "int main(int argc; char *argv[]);" as a prototype, which you must define. Or you include <windows.h>, and "int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow);" is the function you must write. The runtime pulled in would call the appropriate function. "main" would no longer be a special case. This was generally agreed to be the correct solution, but too upsetting for beginners.