ref: 57c8dea5ec7a56ef5ae4e6e816fd40a3e6f23c79 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; }