Build fix for the latest LLVMContext changes (LLVM r75445) This shouldn't break the build with older LLVM revs. We include LLVMContext.h in gen/llvm.h now to make the transition a little bit easier.

interface I {}
class A : I {}
class B : A {}

void main () {
    A a = new A;
    I i = a;

    assert(!cast(B)a);
    assert(!cast(B)i);
}