ref: 4f3a4d8b3da7e7f38b4bc392524944f6f9ccf21f 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; }