That was quite easy to cut and paste and compile:

    $ time ./althttpd-time-parse 
    Test completed in 10518961 us

    real    0m10,521s
    user    0m10,486s
    sys     0m0,004s

The "Test completed" line is from my main() "driver", I wanted to measure time inline too and the measurements seem to agree.

This is on a Dell Latitude featuring a Core i5-7300U at 2.6 GHz, running Ubuntu 20.10.