That's probably to do with exceptions — possibly the only thing that pervades C++ code even if you don't use it. The compiler has to write code so an exception at any point leaves the stack in a sensible way, etc. Try -fno-exceptions (and -fno-rtti might save some memory while you're at it)

Regrettably not every C++ feature is free if you don't use it. But there aren't many that aren't.