fix codegen for pointers to void

test/run_tests.cpp

@@ -1316,6 +1316,19 @@ pub fn main(args: [][]u8) -> %void {
         %%stdout.printf("BAD\n");
     }
     %%stdout.printf("OK\n");
+}
+    )SOURCE", "OK\n");
+
+    add_simple_case("pointer to void return type", R"SOURCE(
+import "std.zig";
+const x = void{};
+fn f() -> &void {
+    %%stdout.printf("OK\n");
+    return &x;
+}
+pub fn main(args: [][]u8) -> %void {
+    const a = f();
+    return *a;
 }
     )SOURCE", "OK\n");
 }