Fix a bunch of IndirectFieldDecl-related warnings.

- Negative ChainingSize doesn't make sense, make it unsigned.

llvm-svn: 119943
diff --git a/clang/tools/libclang/CIndex.cpp b/clang/tools/libclang/CIndex.cpp
index 55331f6..2bc362a 100644
--- a/clang/tools/libclang/CIndex.cpp
+++ b/clang/tools/libclang/CIndex.cpp
@@ -3555,6 +3555,7 @@
   case Decl::TemplateTypeParm:
   case Decl::EnumConstant:
   case Decl::Field:
+  case Decl::IndirectField:
   case Decl::ObjCIvar:
   case Decl::ObjCAtDefsField:
   case Decl::ImplicitParam: