[svn r374] Move label target basic block from AST to IRFunction. This is a first step to allowing labels to be emitted multiple times. (for instance within finally blocks)

enum
{
    LLVMnone,
    LLVMintrinsic,
    LLVMva_arg,
    LLVMva_start,
    LLVMva_intrinsic,
    LLVMnotypeinfo,
    LLVMalloca
};