ref: 1ae5fc01a6e9c6fb1a1befd4c60653a6af10a9e0 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; }