Macro to set the time on an ardunio using https://github.com/PaulStoffregen/Time from the __DATE__ and __TIME__ preprocessor macros.

time.ino

#define SET_TIME() (setTime( \
((__TIME__[0]-'0')*10 + (__TIME__[1]-'0')), \
((__TIME__[3]-'0')*10 + (__TIME__[4]-'0')), \
((__TIME__[6]-'0')*10 + (__TIME__[7]-'0')), \
((__DATE__[4]-'0')*10 + (__DATE__[5]-'0')), \
(__DATE__ [2] == 'n' ? (__DATE__ [1] == 'a' ? 1 : 6) \
    : __DATE__ [2] == 'b' ? 2 \
    : __DATE__ [2] == 'r' ? (__DATE__ [0] == 'M' ? 3 : 4) \
    : __DATE__ [2] == 'y' ? 5 \
    : __DATE__ [2] == 'l' ? 7 \
    : __DATE__ [2] == 'g' ? 8 \
    : __DATE__ [2] == 'p' ? 9 \
    : __DATE__ [2] == 't' ? 10 \
    : __DATE__ [2] == 'v' ? 11 \
    : 12), \
((__DATE__[7]-'0')*1000 + (__DATE__[8]-'0')*100 + \
 (__DATE__[9]-'0')*10 + (__DATE__[10]-'0')) \
))