ref: 30037a7e84c815e217ceacd71a7b7cd3bd47881d dir: /src/libc/time/_newyear.c/
/* * Happy New Year!!!! */ int _newyear(int year) { int day; year += 1900 - 1; day = 1 + year + year/4; day -= year/100; day += year/400; return day % 7; }