ref: 82f0a1d2b47c3d1d7cf573a9f5008f95ddf3d092 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; }