CONSTCOMPLIT

Message        <Context> accepting a compound literal as a constant
               is a language extension.  The compound literal will
               be treated as a cast expression.

Description    A compound literal appears in a context where a
               constant expression is required.  The C standard does
               not list compound literals as a form of operand that
               is allowed in a constant expression, so using a
               compound literal in this context is not maximally
               portable.  The compiler will treat the compound
               literal as if it were a cast expression, which is a
               form of operand that the standard lists as being
               allowed in constant expressions.

User Action    For maximum portability, replace the compound literal
               with a cast expression.