title: Visual C: language modes specified are incompatible
body: <p>Using VisualStudio 2019 on C code:</p>
  <p>When I set the C language spec to anything but Legacy...</p>
  <p><a href="https://i.stack.imgur.com/8w1dU.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8w1dU.png" alt="enter image description here" /></a></p>
  <p>...then I get:</p>
  <p><a href="https://i.stack.imgur.com/zlMUH.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/zlMUH.png" alt="enter image description here" /></a></p>
  <p>I tried different combos of C++/C specs (even though I only have C files, so C++ should not matter) but I always get this error.</p>
  <p>Annoyingly, the error tells me very little. <strong>WHICH</strong> modes are incompatible? How can I get a more verbose error out of the compiler?</p>
  <p>At the very least, it could tell me which flags not to mix.
  This is the command line:</p>
  <pre><code>/GS /W3 /Zi /Od /fp:precise /D &quot;_DEBUG&quot; /D &quot;_CONSOLE&quot; /D &quot;_CRT_SECURE_NO_WARNINGS&quot; /D &quot;_UNICODE&quot; /D &quot;UNICODE&quot; /WX- /std:c11 /Gd /MDd /Fa&quot;x64\Debug\&quot; /EHsc /nologo /Fo&quot;x64\Debug\&quot; /Fp&quot;x64\Debug\turboledzservice.pch&quot; /diagnostics:column 
  </code></pre>