title: error: invalid conversion from 'void (*)(...)' to 'void (*)()'
body: <p>having this problem on Mac with gcc 4.0.1 build 5370, XCode 2.5.
  The code snippet is:</p>
  
  <p>there is a declared function, the second parameter cause the problem:</p>
  
  <pre><code>void ffi_call(ffi_cif *cif, void (*fn)(void), void *rvalue, void **avalue) 
  </code></pre>
  
  <p>calling it like this:</p>
  
  <pre><code>typedef void (*FuncPtr)();
  FuncPtr func = some_function_pointer;
  ffi_call(null, func, ...);
  </code></pre>
  
  <p>cause the error on the third line. Looks like 'void func(void)' is different from 'void func()' for gcc 4.0.1 </p>
  
  <p>Any ideas about any gcc switch or just gcc update would help?
  Thanks for help
  Honza B.</p>