The meat of this patch is in BuildCXXMemberCalLExpr where we make it use

The meat of this patch is in BuildCXXMemberCalLExpr where we make it use
MarkMemberReferenced instead of marking functions referenced directly. An audit
of callers to MarkFunctionReferenced and DiagnoseUseOfDecl also caused a few
other changes:
 * don't mark functions odr-used when considering them for an initialization
   sequence. Do mark them referenced though.
 * the function nominated by the cleanup attribute should be diagnosed.
 * operator new/delete should be diagnosed when building a 'new' expression.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@174951 91177308-0d34-0410-b5e6-96231b3b80d8