title: C++ mark as deprecated
body: <p>I have a method in an interface that I want to deprecate with portable C++.
  When I Googled for this all I got was a Microsoft specific solution; <a href="https://docs.microsoft.com/en-us/cpp/preprocessor/deprecated-c-cpp?view=vs-2017" rel="noreferrer"><code>#pragma deprecated</code></a> and <a href="https://docs.microsoft.com/en-us/cpp/cpp/deprecated-cpp?view=vs-2017" rel="noreferrer"><code>__declspec(deprecated)</code></a>.</p>
  <p>A second prize solution would be to <code>ifdef</code> a MSVC and a GCC solution.</p>