either explicitly set or default_
Dsymbol's affected by this AttribDeclaration
Create a new scope if one or more given attributes are different from the sc's. If the returned scope != sc, the caller should pop the scope after it used.
A hook point to supply scope for members. addMember, setScope, importAll, semantic, semantic2 and semantic3 will use this.
Linkage attribute applied to Dsymbols, e.g. extern(C) void foo().
extern(<linkage>) <decl...>