Counts the number of seconds since start of the game. Unlike
total_ticks, the total_secs counter is suspended when freeze_mode
is nonzero, thus skipping the time spent in menus.
0 .. unlimited
define playtime, 1800; // 30 minutes playtime
while (total_secs < playtime) // loop until total_secs are greater than playtime
exit(); // exit the game
time, time_factor, fps_max, fps_min, fps_lock, total_ticks, wait, total_frames