ref: 1cfe7fded39233cf93f110b0c63b9c5c9f2e7f3e 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; }