User-agent:
Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1
I was made aware that MinGW's implementation of std::chrono might be
lacking, but my testbed is not including that yet, so I cannot
double-check the implementation. Please see this as a motivation to hold
the patch back or check MinGW. I'm sorry for the noise.
