title: How to get XCode 6, LLVM compiler to check c function arguments
body: <p>Does anyone know how to get the Apple LLVM compiler in Xcode 6 to warn if function arguments do not match prototypes?  With default settings, the following does not generate a warning:</p>
  
  <pre><code>void test(int *x)
  {
      printf("%d",*x);
  }
  
  void caller()
  {
      int x = 5;
      test(x);
  }
  </code></pre>
  
  <p>I tried "require function prototypes" in settings, but that just complains when functions do not have a prototype distinct from the declaration.  The problem above occurs whether I have separate prototype or not.  It also seems not to care whether the number of arguments match the declaration or prototype.  Also, I tried -Wstrict-prototypes but that had no effect.  This almost seems like a bug.</p>
  
  <p>Update:  I just tried this with a different Xcode project on a different Mac, and I get the warning as expected.  So, something is broken on that other system.  I would blame it on the project, but I saw the same behavior with 2 unrelated projects.  Both projects were created some years ago, and have been auto-upgraded through various iterations of Xcode, but that is true with the one that works.  The system with the problem is running Yosemite, while the one without a problem is running Mavericks.  Same Xcode 6.1.1.  The problematic system is not at hand right now, or else I would compare behavior of 2 brand new identical projects.</p>