ref: 7f3cb2a9c5b740dc86c4ac4e3d4cb45bb2e69dac 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; }