ref: 5c6a03f4f417d00a6d169cfc9c7e6efae17f4e5e 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; }