ref: 7efba9bdc777541330e1b8fcd4a9e6e61a7a2b2d 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; }