ref: 37f5a0e48ea1a65d4bed95f4e29a2ea9a3b81356 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; }