update CC method:
for the record:
In windows, if you use TortoiseSVN, you just right click on the old cc_branch working copy, then select the context menu item "switch", then put in the trunk address :
svn://svn.berlios.de/codeblocks/trunk
Done.
Then you are using the updated trunk now.
PS:
Not sure why "relocate" command does not works... Maybe the svn command : relocate and switch has different functionality.