std::ostream not static initialized in RTLD_DEEPBIND modules

[jevolk]

Possibly related to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42679

The only occurs for std::cout/std::cerr. Our own ostreams still work. This occurs even if <iostream> is included everywhere and std::ios_base::Init is invoked.

I believe the solution might be to manually mark std::ios_base::Init or a static component inside it as STB_GNU_UNIQUE as it doesn't get tricked by a deep-bind.