title: Visual Studio 2019 always rebuilds everything after I hit the "build" button
body: <p>I'm new to Visual Studio. Now I'm using Visual Studio 2019 to develop Clang&amp;LLVM. I found that every time I right-click the clang executable in the Solution Explorer and choose "Build" or "Debug->Start new instance", VS starts to re-build everything from scratch, although I haven't changed any source file.  Since LLVM is a giant project, this recompilation takes too long. </p>
  
  <p>Is there any solution to make VS smarter to only recompile necessary files (files got changes and their dependencies)? </p>