ref: c854b7aad1a17d9aa69ceda8e3acb5232e9208d4
dir: /libc/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;
}