Added note about multilib options.

  <li>No inline assembly for position independent code.  At the LLVM level,

      everything is position independent.</li>

  <li>We handle <tt>.init</tt> and <tt>.fini</tt> differently.</li>

  <li>You may have to disable multilib support in your target.  Using multilib

      support causes the GCC compiler driver to add a lot of "<tt>-L</tt>"

      options to the link line, which do not relate to LLVM and confuse

      <tt>gccld</tt>.  To disable multilibs, delete any

      <tt>MULTILIB_OPTIONS</tt> lines from your target files.</li>

  <li>Did we mention that we don't support inline assembly?  You'll probably

      have to add some fixinclude hacks to disable it in the system

      headers.</li>