Remove an old workaround that was kept around for ABI-compatibility on x86-64 between different LLVM versions. This means LLVM r67588 is required if you want to compile for x86-64, otherwise the backend will assert when you try to return e.g. struct { int i; char c; } from a function. (In particular, this is no longer compatible with LLVM 2.5) It also means that any code returning small structs on x86-64 will probably need to be recompiled in order to be linkable to code compiled with this change.

enum
{
    LLVMnone,
    LLVMintrinsic,
    LLVMno_typeinfo,
    LLVMno_moduleinfo,
    LLVMalloca,
    LLVMva_start,
    LLVMva_copy,
    LLVMva_end,
    LLVMva_arg,
    LLVMldc,
    LLVMinline_asm
};