Namespace related g++ test failures with --enable-libstdcxx-v3

[Loren James Rittle <rittle at latour dot rsch dot comm dot mot dot com>]

With a dejagnu patch to libgloss.exp to teach it how to locate
libstdc++-v3 libraries and headers in the source and build tree (See
http://sourceware.cygnus.com/ml/libstdc++/2000-q2/msg00245.html), I am
currently getting about 120 failures in g++ tests when I configure and
bootstrap with --enable-libstdcxx-v3.  I have analyzed that most/all
of these new failures under this configuration are due do namespace
issues.  In particular, correct namespace std usage is now enforced
when the compiler is built that way (i.e. -fhonor-std is on by
default) but the failing tests don't qualify all library names
properly.  Another point to consider: currently, libstdc++-v3 is not
providing .h-style compatibility headers unless you explicitly add
-I$prefix/include/g++-v3/backward to the compiler's command line.  [I
think it is just a current Makefile bug but the iostream.h and new.h
compatibility headers aren't being installed at the moment.]

First, assuming a newly failing test currently looks like this:

#include <iostream.h>          

int main() {
  cout<<"hi"<<endl;

  return 0;
}

Would people prefer a patch that fixes the problem as:

(A) Ensure that only g++ tests that are currently failing due to
    namespace issues are run with -I$src/libstdc++-v3/backward only
    when configured with --enable-libstdcxx-v3.

    Note: I don't know how to do this.

(B) Ensure that all g++ tests are run with -I$src/libstdc++-v3/backward
    only when configured with --enable-libstdcxx-v3.

    Note: I know how to do this.  In fact, I have done this and
    started to extend the compatibility headers a bit based upon tests
    which continued to fail. ;-) I am down to 70 failures with another
    20 or so obviously addressable by adding new compatibility headers
    to libstdc++-v3.

(C)

#include <iostream>

int main() {
  std::cout<<"hi"<<std::endl;

  return 0;
}

(D)

#include <iostream>
using namespace std;

int main() {
  cout<<"hi"<<endl;

  return 0;
}

(E) Patch some like C and some like D (and some like A, if possible)
    just to mix it up a bit.

Second, assuming a newly failing test currently looks like this:

#include <iostream>

int main() {
  cout<<"hi"<<endl;

  return 0;
}

Should it be fixed as C or D above?  Or, do you want it converted to
use the compatibility header?

I think using approach B is fine in the first case and, although it
takes a bit more work, approach C is best for the second case.
Comments?

Regards,
Loren