Use LLVM OStream wrapper instead of <iostream> in the logger. llvm::OStream provides all std::ostream functionality (by holding a std::ostream* internally), but * doesn't include <iostream>, avoiding per-file overhead. * allows the stream pointer to be null, and the (inlined) operators do nothing when that's the case. (This also allows removal of the ofstream("/dev/null") hack Logger used when disabled, which presumably wasn't very portable)

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