ref: 17a9a0291b51a6f1bf84e8ee5fdb2f46db8519bb 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; }