ref: 5ff1ec275223dc782ec8be5d219d7d3c7f53c2a9
dir: /sys/src/libc/port/lnrand.c/
#include <u.h>
#include <libc.h>
#define MASK 0x7fffffffL
long
lnrand(long n)
{
long slop, v;
if(n < 0)
return n;
slop = MASK % n;
do
v = lrand();
while(v <= slop);
return v % n;
}