python-ctypes: define a .value() method for enums in java code

ATM, java bindings use Enum.ordinal() to convert the enum name to its value. However, this approach is broken in the case of discontinuous enums such as libvlc_media_option_t.
Java bindings maintainers should convert their code to use the enum.value() method.

bindings/python-ctypes/generate.py

@@ -854,7 +854,11 @@ public enum %s
             # FIXME: write comment
 
             for k, v in values:
-                self.output(fd, "        %s, // %s," % (k, v))
+                self.output(fd, "        %s (%s)," % (k, v))
+            self.output(fd, "");
+            self.output(fd, "        private final int _value;");
+            self.output(fd, "        %s(int value) { this._value = value; }" % javaname);
+            self.output(fd, "        public int value() { return this._value; }");
             self.output(fd, "}")
             fd.close()