progress on struct support

example/structs/structs.zig

@@ -2,6 +2,8 @@ export executable "structs";
 
 use "std.zig";
 
+// Note: this example is not working because codegen is confused about
+// how byvalue structs which are in memory on the stack work
 export fn main(argc : isize, argv : *mut *mut u8, env : *mut *mut u8) -> i32 {
     let mut foo : Foo;
 
@@ -22,6 +24,6 @@ struct Foo {
 
 fn test_foo(foo : Foo) {
     if foo.b {
-        print_str("OK");
+        print_str("OK" as string);
     }
 }