c++/7009: please provide command line option to turn off new include warnings

[Mark Phillips]

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=7009

The new warnings also stop gcc 3.1itself from building...

In my case gcc gettext and libiconv are all installed in the same 
directory, but the existing compiler does not pickup that include/lib dir.

If I use --with-libiconv-prefix=xxx it almost works except, but libjava 
fails because its configure script thinks loads of things are missing 
because the tests fail when they see the unexpected warning:-

cc1plus: warning: changing search order for system directory "/xxx"
cc1plus: warning:   as it has already been specified as a non-system 
directory

A similar problem also effects several other packages.

The new deprecated C++ library warnings also break the configuration of 
some packages (though that can be fixed with a command line flag).

Cheers
Mark