Main function signature equivalency

[ForNeVeR]

C17 standard's section 5.1.2.2.1 Program startup tells us that

The function called at program startup is named main. The implementation declares no prototype
for this function. It shall be defined with a return type of int and with no parameters […] or with two parameters […]: int main(int argc, char *argv[]) { /* ... */ } or equivalent; or in some other implementation-defined manner.

The troubling clause here is "or equivalent". What is considered as an equivalent exactly?

I suppose that:

• declaring more or less arguments isn't "equivalent"
• converting between char*[] and char** and char[]* or whatever is equivalent
• converting of non-const arguments to const ones is equivalent
• declaring main as a function with empty parameter list is equivalent
• declaring main as int main(...) is not equivalent

So, say, int main(int, char*[]) and int main(const int, const char * const *) are allowed, while int main(int, char*) or int main(int, int*) aren't.

As of now, we only support char*[] and not char** for the argv parameter, which should be fixed.