ref: 7f224a8f6d343cf0aaf162cc9b9f7d4d62ac78ac 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; }