ref: 8fdf22d5fb5dca8b0acb1cbfccca1eda33b7d39f dir: /sys/src/ape/lib/ap/gen/abs.c/
#include <stdlib.h> int abs(int a) { if(a < 0) return -a; return a; } long labs(long a) { if(a < 0) return -a; return a; }