ref: 3a2f6031ed0753e6b47676f7f8c5ea2a99e13b4b 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; }