====== A.d ======

module A;

import std.stdio;
import B;

int Avar;

static this()
{
	Avar = 5;
	writefln(Bvar);
}

void main()
{
}

====== B.d ======

module B;

import std.stdio;
import C;

int Bvar;

static this()
{
	Bvar = 5;
	writefln(Avar);
}

====== C.d ======

module C;

public import A;

=================

The program compiles, and outputs:

0
5

(A's constructor gets called before B's).

Related code is in _moduleCtor2 from moduleinit.d - if a module has no static constructors/destructors, any circular references in its imported modules are ignored (the skip parameter).