Fix to make grass render the same on solaris as linux, by doing

pointer comparisons in qsort. This works for glibc according to
the documentation, and appears to work on solaris too.

source/blender/blenkernel/intern/particle_system.c

@@ -845,8 +845,16 @@ static int compare_orig_index(const void *p1, const void *p2)
 
 	if(index1 < index2)
 		return -1;
-	else if(index1 == index2)
-		return 0;
+	else if(index1 == index2) {
+		/* this pointer comparison appears to make qsort stable for glibc,
+		 * and apparently on solaris too, makes the renders reproducable */
+		if(p1 < p2)
+			return -1;
+		else if(p1 == p2)
+			return 0;
+		else
+			return 1;
+	}
 	else
 		return 1;
 }