docs: Sketch docs for llvm-build tool.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143627 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/LLVMBuild.html b/docs/LLVMBuild.html
index 904d0e5..bb1883a 100644
--- a/docs/LLVMBuild.html
+++ b/docs/LLVMBuild.html
@@ -88,6 +88,11 @@
   developers who are not working on the build system would only ever need to
   modify the contents of the <i>LLVMBuild.txt</i> description files (although we
   have not reached this goal yet).</p>
+
+  <p>For more information on the utility tool we provide to help interfacing
+  with the build system, please see
+  the <a href="CommandGuide/html/llvm-build.html">llvm-build</a>
+  documentation.</p>
 </div>
 
 <!-- *********************************************************************** -->