> Then running b.c will segfault

why would it not ? On one side you declare an int array of size 1, on the other side you declare a pointer. Think about what's going on with the bytes :

    int n[] = { 1 };

will look exactly the same in memory than

    int n = 1;

which is of course not compatible with

    int* n = 1; 

Arrays by themselves have no indirection in C.

=> https://godbolt.org/g/xwT7uW