Comment 13 for bug 1074353

> error: invalid use of incomplete type ‘const struct Widelands:

this indicates that the compiler does not know how the class looks. that means that it is conly forward declared, but the compiler did not see a definition. A #include in the .cc file will fix this.
Forward declaring is much cheaper than #including a file, that is when you are in a .h file and you only use pointers to a class, you only forward declare it:

class A
int foo(A* pointer_to_A); // this will compile fine, compiler does not need to know about the internals of A.

int foo(A* pointer_to_A) { pointer_to_A->method_blub(); } // now the compiler needs to know about A, so include it's header.

Also, there was a typo: the class is called WareDescr not, Ware_Descr.

I added wrappings for becomes in the latest revision and enabled get_ware_description too. Could you merge trunk before continuing? there are some merge conflicts again.