Bug#898323: g++-8 -m32 do not find bits/c++config.h

[Bill Allombert <ballombe@debian.org>]

Package: g++-8
Version: 8.1.0-1
Severity: normal

Hello GCC maintainers,

trying to the attached dummy file with g++-8 fails:

g++-8 -m32 hello.c
In file included from /usr/include/c++/8/stdlib.h:36,
                 from hello.c:1:
/usr/include/c++/8/cstdlib:41:10: fatal error: bits/c++config.h: No such file or directory
 #include <bits/c++config.h>
          ^~~~~~~~~~~~~~~~~~
compilation terminated.

g++-8-multilib is installed.
This work with g++-7 and g++-6
Maybe this is related to
 "* Stop providing the 8.x.y symlinks in gcc_lib_dir and incluce/c++.  "

ii  g++-8              8.1.0-1        amd64          GNU C++ compiler
ii  g++-8-multilib     8.1.0-1        amd64          GNU C++ compiler (multilib support)
ii  lib32stdc++-8-dev  8.1.0-1        amd64          GNU Standard C++ Library v3 (development

Cheers,
Bill.

#include <stdlib.h>
int main(void)
{
  return 1;
}