How essential are the stl libraries for the operation of eigen?

I'm trying to use eigen in an embedded c++ project where stl libraries are difficult to include.

Eigen includes <complex> and < iostreams>.

I don't care about these features, and would be happy if there was a compile time flag to disable that functionality. Is that doable? How hard would that be to do?

Does anything else require in the core of eigen's functionality need the stl?
Thanks!

It also requires standard math functions (std::min, std::sqrt, etc.), std::numeric_limits, STL's functors (std::plus, std::binder*, etc.), std::swap, and probably more. If want to see all usages do:

$ grep "std::" Eigen/src/Core/