add a link to the libc++ website

llvm-svn: 160553
diff --git a/libcxxabi/www/index.html b/libcxxabi/www/index.html
index 8b0448d..6d37283 100644
--- a/libcxxabi/www/index.html
+++ b/libcxxabi/www/index.html
@@ -48,7 +48,7 @@
 
     <ul>
         <li>Correctness as defined by the C++11 standard.</li>
-        <li>Provide a portable sublayer to ease the porting of libc++</li>
+        <li>Provide a portable sublayer to ease the porting of <a href="http://libcxx.llvm.org/">libc++</a></li>
         <li>On Mac OS X, be ABI compatible with the existing low-level support.</li>
     </ul>