seems like a bug to me. the spec is pretty clear:
6.7.2.2 Enumeration specifiers
Syntax
[#1]
enum-specifier:
enum identifier-opt { enumerator-list }
enum identifier-opt { enumerator-list , }
enum identifier
enumerator-list:
enumerator
enumerator-list , enumerator
enumerator:
enumeration-constant
enumeration-constant = constant-expression
Constraints
[#2] The expression that defines the value of an enumeration
constant shall be an integer constant expression that has a
value representable as an int.
russ