update swig on windows

winx64/bin/swigwin-4.0.0/Examples/ocaml/argout_ref/example.c

@@ -0,0 +1,19 @@
+/* File : example.c */
+
+/* Compute the greatest common divisor of positive integers */
+int gcd(int x, int y) {
+  int g;
+  g = y;
+  while (x > 0) {
+    g = x;
+    x = y % x;
+    y = g;
+  }
+  return g;
+}
+
+extern "C" void factor( int &x, int &y ) {
+    int gcd_xy = gcd( x,y );
+    x /= gcd_xy;
+    y /= gcd_xy;
+}