title: Does any C library implement C11 threads for GNU/Linux?
body: <p>There have been <strong><em>a lot</em></strong> of questions about C11 and C11 threading, but I don't see a definitive answer anywhere: </p>
  
  <p><strong>Does <em>any</em> C library implement the C11 threading interface usable on GNU/Linux-like?</strong> e.g., provide the "optional" <code>&lt;threads.h&gt;</code> and the <a href="http://en.cppreference.com/w/c/thread" rel="noreferrer">thread support library</a> like <code>thrd_create()</code>, from <a href="http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf" rel="noreferrer">the C11 standard</a> near p. 376.</p>
  
  <p>Ideally, I'd like to find a library that is common-ish, open-source or free, for common/generic/multi architecture (e.g., GNU/Linux, x86_64, or portable-ish).</p>
  
  <p>A few of the more helpful and relevant SO links:</p>
  
  <ul>
  <li><a href="https://stackoverflow.com/questions/8859394/c11-thread-h-in-gcc">this one</a> and <a href="https://stackoverflow.com/questions/22875545/c11-gcc-threads-h-not-found">this one</a> on <code>glibc</code>;</li>
  <li><a href="https://stackoverflow.com/questions/8876043/multi-threading-support-in-c11">this one</a> that's talking about the standard;</li>
  <li><a href="https://stackoverflow.com/questions/16244153/clang-c11-threads-h-not-found">this one</a> about <code>clang</code>;</li>
  <li><a href="https://stackoverflow.com/questions/9804594/compilers-that-support-c11">this one</a> about C11 in general and <a href="https://stackoverflow.com/questions/23400686/current-c11-implementation-status-threads-h">this one</a> about Windows and other platforms;</li>
  <li>a lot more about <em>C++11</em> threading, but I am only interested in C11.</li>
  </ul>
  
  <p>Some non-starter options for libraries:</p>
  
  <ul>
  <li><a href="http://www.gnu.org/software/libc/libc.html" rel="noreferrer"><code>glibc</code></a> library <a href="http://gcc.gnu.org/wiki/C11Status" rel="noreferrer">does not</a>; there is an <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=14092" rel="noreferrer">open bug</a> since 2012; there was <a href="https://sourceware.org/ml/libc-alpha/2014-02/msg00781.html" rel="noreferrer">GSoC proposal</a> but seems <a href="http://www.google-melange.com/gsoc/projects/list/google/gsoc2014" rel="noreferrer">not accepted</a>;</li>
  <li><a href="http://llvm.org" rel="noreferrer">LLVM/Clang</a> project does not have a C library;</li>
  <li><strike><a href="http://wiki.musl-libc.org/wiki/Compatibility" rel="noreferrer">musl</a> library <a href="http://nsz.repo.hu/git/?p=musl-tables;a=blob_plain;f=tab_c11.html;hb=HEAD" rel="noreferrer">does not</a>;</strike> -- now does! See edit below and <a href="https://stackoverflow.com/a/28412024/3562032">answer</a>.</li>
  <li><a href="http://sourceware.org/newlib/" rel="noreferrer">Newlib</a> library supports threading (<a href="http://sourceware.org/newlib/libc.html" rel="noreferrer">docs</a>), but not using <code>pthread</code> nor C11 threads;</li>
  <li><a href="http://www.uclibc.org" rel="noreferrer">uClibc</a> does not;</li>
  <li><a href="http://www.etalabs.net/compare_libcs.html" rel="noreferrer">this comparison</a> chart, which is dubious (e.g., I see no evidence in musl sources for C11 thread-local storage support);</li>
  <li>Some various posts about <a href="http://www.phoronix.com/scan.php?page=news_item&amp;px=MTI5Nzk" rel="noreferrer">BSD</a>,</li>
  <li><a href="http://www.smorgasbordet.com/pellesc/" rel="noreferrer">Pelles</a>, which appears closed and Windows-only.</li>
  </ul>
  
  <p>I am <strong><em>not</em></strong> interested in POSIX threads (many fine options), Windows, an IDE, nor C++11 (I know that GNU <code>libstdc++</code> and LLVM/Clang <code>libc++</code> provide C++11's <code>std::thread</code>, which uses <code>-pthread</code>)</p>
  
  <p>Thanks!</p>
  
  <hr>
  
  <p>(re-)Edit: question re-opened, so <a href="https://stackoverflow.com/a/28412024/3562032">migrated content to answer</a> to clean up.</p>