Delay emitting members of dllexport classes until the class is fully parsed (PR23542)

Delay emitting members of dllexport classes until the class is fully parsed (PR23542)

This enables Clang to correctly handle code such as:

  struct __declspec(dllexport) S {
    int x = 42;
  };

where it would otherwise error due to trying to generate the default
constructor before the in-class initializer for x has been parsed.

Differential Revision: http://reviews.llvm.org/D11850

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@245139 91177308-0d34-0410-b5e6-96231b3b80d8