Print log/error messages on stderr, not stdout

There are a couple of places where libc++ prints log/error messages to
stdout on its own. This may of course interfere with the output
generated with applications. Log/error messages should be directed to
stderr instead.

Differential Revision:	http://reviews.llvm.org/D8135
Reviewed by:	marshall


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@231767 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed