ref: ca2fa9596b5d0d893be28c6e8fd8a52a89a0c3c6 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; }