This compilation error from the localtime.c in 2013d looks like an actual problem. I think time_t is generally an integer type of some sort.

Built using the clang compiler on Linux.

localtime.c:1517:34: error: implicit conversion from 'double' to 'time_t' (aka 'long') changes value from 0.5 to 0 [-Werror,-Wliteral-conversion]
                register time_t         half_second = 0.5;
                                        ~~~~~~~~~~~   ^~~
1 error generated.

Thanks,
  -- Andy Heninger