--- system.c.orig	2012-02-22 22:46:14.000000000 -0200
+++ system.c	2012-02-22 22:47:51.000000000 -0200
@@ -1161,7 +1161,14 @@
 
 int groups_max(void)
 {
-#if defined(SYSCONF_SC_NGROUPS_MAX)
+#if defined(DARWINOS)
+	/* On OS X, sysconf(_SC_NGROUPS_MAX) returns 16
+	 * due to OS X's group nesting and getgrouplist
+	 * will return a flat list; users can exceed the
+	 * maximum of 16 groups. And easily will.
+	 */
+	return 32; // NGROUPS_MAX is defined, hence the define above is void.
+#elif defined(SYSCONF_SC_NGROUPS_MAX)
 	int ret = sysconf(_SC_NGROUPS_MAX);
 	return (ret == -1) ? NGROUPS_MAX : ret;
 #else