GCC, Clang, and MSVC all still duplicate c* header definitions into the global namespace by default as far as I'm aware.

In fact, the last time I checked, the MSVC cstdio header was implemented more or less like this:

    namespace std {
        #include <stdio.h>
    }

    using namespace std;

It's kind of crazy how major compilers have been ignoring the standard for so long that people consider a standard compliant compiler to be weird and broken.