Is it possible to declare a friend function as static?

Quoting N3691 – §11.3/4 [class.friend]

A function first declared in a friend declaration has external linkage (3.5). Otherwise, the function retains its previous linkage (7.1.1).

So you need to declare the function as static prior to declaring it as a friend. This can be done by adding the following declarations above the definition of A.

class A;  // forward declaration, required for following declaration
static void IncrementValue(A&); // the friend declaration will retain static linkage