Instructions for updating LLVM Subversion checkout (Patch by Isaac Ke…

…arse)

git-svn-id: http://svn.macosforge.org/repository/ruby/MacRuby/trunk@4997 23306eb0-4c56-4727-a40e-e92c0eb68959

README.rdoc

@@ -39,9 +39,16 @@ http://macruby.org
   unresponsive during compilation. To use multiple cores pass the `-j N'
   option, where `N' stands for the number of cores you'd like to use. So for a
   Core Duo the command would look like:
-  
+
     $ env UNIVERSAL=1 UNIVERSAL_ARCH="i386 x86_64" CC=/usr/bin/gcc CXX=/usr/bin/g++ make -j2
-
+
+  If you would prefer to update an existing LLVM Subversion working copy you 
+  need to be careful to remove any previous build files before you compile:
+
+    $ svn status --no-ignore | awk '{print $2}' | xargs rm -rf
+    $ svn revert -R .
+    $ svn switch https://llvm.org/svn/llvm-project/llvm/tags/RELEASE_28
+
 === Build Instructions
 
 You can build MacRuby by doing the following command: