Make format strings visible only to time_fun.cpp. Qualify with 'constexpr' since format strings are compile-time values.
Make format strings visible only to time_fun.cpp.
Qualify with 'constexpr' since format strings are compile-time values.

greatwolf/blackbird,butor/blackbird,greatwolf/blackbird,butor/blackbird,butor/blackbird,greatwolf/blackbird