compilers that support thread-local storage?

[Michael Dickens]

I'm wondering what the correct blacklist is to get compilers that support thread local storage.

I've found some Portfiles that state just:
{{{
compiler.blacklist-append {clang < 800.0.38}
}}}
which isn't enough since I know that the old Apple GCC and LLVM versions from 4.2 and older won't work ... so adding also:
{{{
compiler.blacklist-append cc {*gcc-3*} {*gcc-4.[0-2]}
}}}

What I don't know is which version of GCC did thread local storage start? Maybe with c++11, which would be IIRC 4.6, so also:
{{{
compiler.blacklist-append {*gcc-4.[3-5]}
}}}

Or: can I just use the C++11 PortGroup?

What's the best / correct way to do this?

Thx! - MLD