[Issue 22886] ImportC: forward declaration of struct in a function prototype leads to "redeclaration with different type" error.

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=22886

--- Comment #1 from dave287091 at gmail.com ---
This also fails:

// test.c
struct config *Configlist_add(int);
struct config *Configlist_add(int); // Error: function `test.Configlist_add`
redeclaration with different type  

struct config {
  int dot;
};

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