Fix savannah #99234.
The issue we experienced is that we couldn't pipe the output in the terminal.
The reason is that we were using llvm::outs() which closes explicitly the file
descriptor (thanks Axel for the help debugging).
We introduce our custom stream, which keeps the file descriptor open so that
we can use it in pipes. For debugging purposes, however we use/should use llvm::errs()

The lesson learned:
DONT USE LLVM::OUTS() ANYMORE!


git-svn-id: https://root.cern.ch/svn/root/trunk@48316 27541ba8-7e3a-0410-8455-c3a389f83636