title: issue when trying to build llvmcore at intrinsic generation
body: <p>I am trying to compile the llvm 2336.11. I configured it with: </p>
  
  <pre><code>export CXX=/opt/local/bin/llvm-g++-4.2
  export CC=/opt/local/bin/llvm-gcc-4.2
  ln -s /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk/usr/include/mach/x86_64/ /usr/include/mach/x86_64
  ln -s /usr/local/Cellar/binutils/2.23.1/x86_64-apple-darwin12.2.0/bin/ar /usr/bin/ar
  ln -s /Applications/Xcode.app/Contents/Developer/usr/bin/ranlib /usr/bin/ranlib
  ln -s /Applications/Xcode.app/Contents/Developer/usr/bin/nm /usr/bin/nm
  
  ../llvmgcc42-2336.11/llvmcore/configure --prefix=/Users/patrick.muscat/Documents/crosscompil/llvmbin/ --enable-assertions=no --enable-optimized=yes
  </code></pre>
  
  <p>But i get this:</p>
  
  <pre><code>llvm[1]: Building Intrinsics.gen.tmp from Intrinsics.td
  /Users/patrick.muscat/Documents/crosscompil/llvmbuild/Release-Asserts/bin/tblgen: ERROR: Couldn't find the `Intrinsic' class!
  make[1]: *** [/Users/patrick.muscat/Documents/crosscompil/llvmbuild/lib/VMCore/Release-Asserts/Intrinsics.gen.tmp] Error 1
  make[1]: Leaving directory `/Users/patrick.muscat/Documents/crosscompil/llvmbuild/lib/VMCore'
  make: *** [all] Error 1
  </code></pre>
  
  <p>Then i modified the source to show the available definitions and classes adding Records.dump() in Record.cpp where the error text appears and i get this (empty):</p>
  
  <pre><code>------------- Classes -----------------
  ------------- Defs -----------------
  </code></pre>
  
  <p>Does anyone have an explaination ?</p>
  
  <p>Thanks in advance</p>