ref: 3e7ad6ef67711cbf73c61d1ab2d77c82a2ff7b3c 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; }