title: ‘__gnuc_va_list’ has not been declared
body: <p>I try to build large project with many directories and sub-directories, some of them are being used to create different libs.
   using GNU make using same compilation flags. most of the folder are successfully built, but in a specific folder the build failed, and it gets many errors that some definitions is missing.
  For instance, the first error is:</p>
  
  <blockquote>
    <p>In file included from /usr/include/c++/4.8.2/cwchar:44:0,
                     from /usr/include/c++/4.8.2/bits/postypes.h:40,
                     from /usr/include/c++/4.8.2/iosfwd:40,
                     from /usr/include/c++/4.8.2/memory:72,
     ... </p>
    
    <p>/usr/include/wchar.h:614:9: error: ‘__gnuc_va_list’ has not been
    declared</p>
  
  <pre><code>     __gnuc_va_list __arg
  </code></pre>
  </blockquote>
  
  <p>)
  this error comes from simple #include  at of the files in this lib, but same sort of error happens for any file and for different standard library headers.</p>
  
  <p>The strength thing is that this project was completely successfully built before i pulled some updates from remote repository. at this merge no changes were done to this file.
  Tried to use</p>
  
  <pre><code>g++ -E /usr/include/wchar.h | grep __gnuc_va_list | head -1
  </code></pre>
  
  <p>result is:</p>
  
  <blockquote>
    <p>typedef __builtin_va_list __gnuc_va_list;</p>
  </blockquote>
  
  <p>As i see <a href="https://stackoverflow.com/a/49738312/3965628">at this answer</a>, __builtin_va_list shuould be created by gcc, and it probably did create it-  otherwise many other files were failed to compile</p>
  
  <p>I can't understand why it happens and why only at this folder/lib.</p>