"This patch addresses two FIXME on ObjCCategoryImplDecl:

/// FIXME: Like ObjCImplementationDecl, this should not be a NamedDecl!
/// FIXME: Introduce a new common base class for ObjCImplementationDecl and ObjCCategoryImplDecl

It adds an IndentifierInfo ivar to the ObjCCategoryImplDecl, so it can inherits from Decl and not NamedDecl (I'm not sure about the memory management of this ivar).

And now that both ObjCImplementationDecl and ObjCCategoryImplDecl have the same super classes, it allow creation of a common base class:  ObjCImplDecl"

Patch by Jean-Daniel Dupas!

llvm-svn: 65703