node: tag Encode and friends NODE_EXTERN
node: tag Encode and friends NODE_EXTERN

Makes the symbols visible on Windows. They were already visible on Unices.

Fixes #3811.

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node