fix enum with const value declaration

[felipensp]

Fix #50

enum { J = 1 };

was generating V

const ( // empty enum
	j = 0
)

[ArtemkaKun]

Hi, cool stuff. CI errors seem to be unrelated to changes. Can you also add a test (Maybe just copy-paste C and the expected code from the issue)?

[felipensp]

Hi, cool stuff. CI errors seem to be unrelated to changes. Can you also add a test (Maybe just copy-paste C and the expected code from the issue)?

Sure. I've added.