[Bug libstdc++/82417] Macros from <complex.h> defined in C++11

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82417

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I'm not opposed to a warning in principle, but I'd prefer it to be one
controllable by a -Wxxx option. I don't know how to do that using the
preprocessor, so we'd have to do something like:

#ifndef _GLIBCXX_NO_CCOMPLEX_WARNING
# warning "Including <ccomplex> makes no sense. Define
_GLIBCXX_NO_CCOMPLEX_WARNING to disable this warning."
#endif

And that is a bit ugly.