Clang builds a working 2.6.36 Kernel

Much worse than that. It allows (and kernel does *not* use, unless something has drastically and cretinously changed) things like that:

extern void g(int *);
void f(int m, int n)
{
struct foo {
int a[n];
int b[n][m + 69];
} x;
g(&x.b[1][1]);
}

Yes, gcc is that sick.