[ANN] --enable-dbgutil: everyone gets a Debug STL!

[Tor Lillqvist]

It is known that Apple has stopped following upstream libstdc++ (just
like they have stopped following upstream GCC). Thus I assume this bug
in libstdc++ is not going to be fixed. Can it BTW be reproduced on a
Linux version that still uses libstdc++ version 4.2.1?

I wonder if there is some simple hack we could use to work around the problem?

The C++ library Apple is switching to is libc++,
http://libcxx.llvm.org . It doesn't seem to be the default yet when
running clang++ from the command line. However, when setting up
project in Xcode, it does by default use libc++. The clang++
command-line option to use it is -stdlib=libc++.

This problem indeed does not occur with libc++, but then, libc++ does
not really have something that would work and correspond to
_GLIBCXX_DEBUG anyway, so that is not as such any more fun than not
using _GLIBCXX_DEBUG...

(There is a _LIBCPP_DEBUG, but that is not really supposed to be
useful yet, if ever,
http://clang-developers.42468.n3.nabble.com/questions-about-libc-s-LIBCPP-DEBUG-tp4030016p4030019.html
)

I wonder if we should enforce using libc++ instead of GNU libstdc++
when using Clang on OS X and not targeting 10.6? (Trying to build with
-stdlib=libc++ and -mmacosx-version-min=10.6  results in "clang:
error: invalid deployment target for -stdlib=libc++ (requires OS X
10.7 or later)") Nah, probably not useful as long as our deployment
target is 10.6. Better to just forget about _GLIBCXX_DEBUG on OS X if
the ostringstream problem can't be worked around.

--tml