Add a note about the Solaris configure problem that Tanya's seen.

llvm-svn: 24236
diff --git a/llvm/docs/ReleaseNotes.html b/llvm/docs/ReleaseNotes.html
index 430200b..4337480 100644
--- a/llvm/docs/ReleaseNotes.html
+++ b/llvm/docs/ReleaseNotes.html
@@ -318,6 +318,19 @@
 
 <!-- ======================================================================= -->
 <div class="doc_subsection">
+  <a name="build">Known problems with the Build System</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+  <li>The <a href="http://llvm.org/PR656">configure script sometimes fails on Solaris/Sparc</a>.</li>
+</ul>
+</div>
+
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
   <a name="core">Known problems with the LLVM Core</a>
 </div>