Javascript implementation of C stdlib random() function (the spec specifies no algorithm, the one of the GNU GLIBC is used). For a description of the algorithm, see: http://www.mathstat.dal.ca/~selinger/random/. I just realised that I was not logged in when I created the gist, so it's also available as an anonymous gist.

c_random.js

function Random(seed) {
/*JS implementation of GNU C stdlib random() algorithm described here:
	http://www.mathstat.dal.ca/~selinger/random/
*/
/*Usage : 
r = new Random(1);
r.random();
this will generate the same sequence of pseudo-random numbers as C stdlib's random().
*/

	seed = seed>>>0;

	var r = [], i;

	r[0] = seed;

	for (i=1; i<31; i++) {
		r[i] = (16807 * (r[i-1]>>>0)) % 2147483647;
		if (r[i] < 0) {
			r[i] += 2147483647;
		}
	}
	for (i=31; i<34; i++) {
		r[i] = r[i-31];
	}
	for (i=34; i<344; i++) {
		r[i] = (r[i-31] + r[i-3])|0;
	}

	//Here i=344
	i=343;

	this.random = function() {
		i++;
		r[i] = (r[i-31] + r[i-3])|0;
		return (r[i]>>>1);
	}
}