Extra whitespace or the specific choices of spaces is entirely irrelevant in the context of defining an enum
and the enumerators are separate by comma. Thus, the quote way to define enumerators is certainly covered by the C++ standard (all versions thereof) and by C99 and later standards (I don't make any claims for C90 because I'm not sufficiently familiar with C90 and I don't have it handy but I think the enum
definition works there, too). Also, in all these cases the enum
can be anonymous.
The interesting question is support for a trailing comma after the last enumerators, e.g.
enum { value, };
which isn't covered by all standards. It is covered in C99 and later. I don't think a trailing comma is supported by C++03 but it is supported by C++11.