[NaCl SDK] Cleanup references to old newlib toolchain

native_client_sdk/doc_generated/sdk/release-notes.html

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 <section id="release-notes">
 <span id="sdk-release-notes"></span><h1 id="release-notes"><span id="sdk-release-notes"></span>Release Notes</h1>
 <p>The dates in the following release notes denote when Chrome and the NaCl SDK
 reached canary status. The stable release is typically 6 weeks later.</p>
+<h2 id="chrome-pepper-49">Chrome/Pepper 49</h2>
+<ul class="small-gap">
+<li>GCC-based newlib toolchains removed from the SDK.  These have been
+superseded by the nacl-clang toolchain which also produces statically linked
+architecture specific nexe files.</li>
+<li>gtest/gmock no longer shipped as pre-built libraries.  This is in-line with
+normal gtest/gmock usage guidelines.  Projects wishing to use gtest/gmock must
+now add explicit include paths and compile gtest-all.cc locally.</li>
+</ul>
 <h2 id="chrome-pepper-45-10-july-2015">Chrome/Pepper 45 (10 July 2015)</h2>
 <h3 id="pepper">Pepper</h3>
 <ul class="small-gap">
 <li>UDP Socket Multicast API in stable (PPB_UDP_SOCKET 1.2).</li>
 </ul>
 <h2 id="chrome-pepper-43-03-april-2015">Chrome/Pepper 43 (03 April 2015)</h2>
 <h3 id="pnacl">PNaCl</h3>
 <ul class="small-gap">
 <li>The C11/C++11 <code>acquire</code>, <code>release</code>, and <code>acq_rel</code> memory orders are now
 generated by default. The in-browser Chrome 42 translator supports them, the
@@ skipping 624 matching lines @@
 </ul>
 <h3 id="id31">PPAPI</h3>
 <ul class="small-gap">
 <li>The <code>CompletionCallbackFactory</code> class template now takes a thread traits
 class as its second parameter. For details see the <a class="reference external" href="/native-client/pepper_stable/cpp/classpp_1_1_completion_callback_factory#details">CompletionCallbackFactory
 class template reference</a>.</li>
 </ul>
 </section>
 
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